Genetic correlation

In multivariate behavioral & quantitative genetics, a genetic correlation (denoted $r_{g}$ or $r_{a}$ ) is the proportion of variance that two traits share due to genetic causes,^[1]^[2] the correlation between the genetic influences on a trait and the genetic influences on a different trait^[3]^[4]^[5]^[6]^[7]^[8]^[9] estimating the degree of pleiotropy or causal overlap. A genetic correlation of 0 implies that the genetic effects on one trait are independent of the other, while a correlation of 1 implies that all of the genetic influences on the two traits are identical. The bivariate genetic correlation can be generalized to inferring genetic latent variable factors across >2 traits using factor analysis. Genetic correlation models were introduced into behavioral genetics in the 1970s-1980s.

Genetic correlations have applications in validation of GWAS results, breeding, prediction of traits, and discovering the etiology of traits & diseases.

They can be estimated using twin studies and molecular genetics. Genetic correlations have been found to be common in non-human genetics^[10] and to be broadly similar to their respective phenotypic correlations,^[11] but also in human traits.^[12]^[13]^[14]^[15]^[16]^[17]^[18]^[19] This finding of widespread pleiotropy has implications for artificial selection in agriculture, interpretation of phenotypic correlations, attempts to use Mendelian randomization in causal inference,^[20]^[21]^[22]^[23]^[24] the understanding of the biological origins of complex traits, and the design of GWASes.

A genetic correlations is to be contrasted with environment correlations between the environments affecting two traits (eg if poor nutrition in a household caused both lower IQ and height); a genetic correlation between two traits can contribute to the observed (phenotypic) correlation between two traits, but genetic correlations can also be opposite observed phenotypic correlations if the environment correlation is sufficiently strong in the other direction, perhaps due to tradeoffs or specialization.^[25]^[26]

Interpretation

Genetic correlations are not the same as heritability, as it is about the overlap between the two sets of influences and not their absolute magnitude; two traits could be both highly heritable but not be genetically correlated or have small heritabilities and be completely correlated (as long as the heritabilities are non-zero).

For example, consider two traits - dark skin and black hair. These two traits may individually have a very high heritability (most of the population-level variation in the trait due to genetic differences, or in simpler terms, genetics contributes significantly to these two traits), however, they may still have a very low genetic correlation if, for instance, these two traits were being controlled by different, non-overlapping, non-linked genetic loci.

A genetic correlation between two traits will tend to produce phenotypic correlations - eg the genetic correlation between intelligence and SES^[14] or education and family SES^[27] implies that intelligence/SES will also correlate phenotypically. The phenotypic correlation will be limited by the degree of genetic correlation and also by the heritability of each trait. The expected phenotypic correlation is the bivariate heritability' and can be calculated as the square roots of the heritabilities multiplied by the genetic correlation. (Using a Plomin example,^[28] for two traits with heritabilities of 0.60 & 0.23, $r_{g}=0.75$ , and phenotypic correlation of r=0.45 the bivariate heritability would be ${\sqrt {0.60}}\cdot 0.75\cdot {\sqrt {0.23}}=0.28$ , so of the observed phenotypic correlation, 0.28/0.45 = 62% of it is due to genetics.)

Cause

Genetic correlations can arise due to:^[17]

linkage disequilibrium (two neighboring genes tend to be inherited together, each affecting a different trait)
biological pleiotropy (a single gene having multiple otherwise unrelated biological effects)
mediated pleiotropy (a gene causes trait X and trait X causes trait Y).
biases: population stratification such as ancestry or assortative mating (sometimes called "gametic phase disequilibrium"), spurious stratification such as ascertainment bias/self-selection^[29] or Berkson's paradox, or misclassification of diagnoses

Uses

Causes of changes in traits

Genetic correlations are scientifically useful because genetic correlations can be analyzed over time within an individual longitudinally^[30] (eg intelligence is stable over a lifetime, due to the same genetic influences - childhood genetically correlates $r_{g}=0.62$ with old age^[31]), or across studies or populations or ethnic groups/races, or across diagnoses, allowing discovery of whether different genes influence a trait over a lifetime (typically, they do not^[3]), whether different genes influence a trait in different populations due to differing local environments, whether there is disease heterogeneity across times or places or sex (particularly in psychiatric diagnoses there is uncertainty whether 1 country's 'autism' or 'schizophrenia' is the same as another's or whether diagnostic categories have shifted over time/place leading to different levels of ascertainment bias), and to what degree traits like autoimmune or psychiatric disorders or cognitive functioning meaningfully cluster due sharing a biological basis and genetic architecture (for example, reading & mathematics disability genetically correlate, consistent with the Generalist Genes Hypothesis, and these genetic correlations explain the observed phenotypic correlations or 'co-morbidity';^[32] IQ and specific measures of cognitive performance such as verbal, spatial, and memory tasks, reaction time, long-term memory, executive function etc all show high genetic correlations as do neuroanatomical measurements, and the correlations may increase with age, with implications for the etiology & nature of intelligence). This can be an important constraint on conceptualizations of the two traits: traits which seem different phenotypically but which share a common genetic basis require an explanation for how these genes can influence both traits.

Boosting GWASes

Genetic correlations can be used in GWASes by using polygenic scores or genome-wide hits for one (often more easily measured) trait to increase the prior probability of variants for a second trait; for example, since intelligence and years of education are highly genetically correlated, a GWAS for education will inherently also be a GWAS for intelligence and be able to predict variance in intelligence as well^[33] and the strongest SNP candidates can be used to increase the statistical power of a smaller GWAS,^[34] or one could do a GWAS for multiple traits jointly.^[35]

Breeding

Hairless dogs have imperfect teeth; long-haired and coarse-haired animals are apt to have, as is asserted, long or many horns; pigeons with feathered feet have skin between their outer toes; pigeons with short beaks have small feet, and those with long beaks large feet. Hence if man goes on selecting, and thus augmenting any peculiarity, he will almost certainly modify unintentionally other parts of the structure, owing to the mysterious laws of correlation.
— Charles Darwin, The Origin of Species, 1859

Genetic correlations are also useful in applied contexts such as plant/animal breeding by allowing substitution of more easily measured but highly genetically correlated characteristics (particularly in the case of sex-linked or binary traits under the liability-threshold model, where differences in the phenotype can rarely be observed but another highly correlated measure, perhaps an endophenotype, is available in all individuals), compensating for different environments than the breeding was carried out in, making more accurate predictions of breeding value using the multivariate breeder's equation as compared to predictions based on the univariate breeder's equation using only per-trait heritability & assuming independence of traits, and avoiding unexpected consequences by taking into consideration that artificial selection for/against trait X will also increase/decrease all traits which positively/negatively correlate with X.^[36]^[37]^[38]^[39]^[40]

Breeding experiments on genetically correlated traits can measure the extent to which correlated traits are inherently developmentally linked & response is constrained, and which can be dissociated.^[41] Some traits, such as the size of eye spots on the butterfly Bicyclus anynana can be dissociated in breeding,^[42] but other pairs, such as eye spot colors, have resisted efforts.^[43]

Computing the genetic correlation

Genetic correlations require a genetically informative sample. They can be estimated by using breeding experiments on two traits of known heritability and selecting on one trait to measure the change in the other trait (allowing inferring the genetic correlation), family/adoption/twin studies (analyzed using SEMs or DeFries-Fulker extremes analysis), molecular estimation of relatedness such as GCTA,^[44] methods employing polygenic scores like LD score regression,^[15]^[45] BOLT-REML^[46] or HESS,^[47] comparison of genome-wide SNP hits in GWASes (as a loose lower bound), and phenotypic correlations of populations with at least some related individuals.^[48] (As with estimating SNP heritability, the better computational scaling & the ability to estimate only using public polygenic scores is a particular advantage for LD score regression over competing methods, and combined with the increasing availability of polygenic scores from datasets like the UK Biobank has led to an explosion of genetic correlation research in the 2010s.) The methods are related to Haseman-Elston regression & PCGC regression.^[49]

One way to consider it is using trait X in twin 1 to predict trait Y in twin 2 for monozygotic and dizygotic twins (ie using twin 1's IQ to predict twin 2's brain volume); if this cross-correlation is larger for the more genetically-similar monozygotic twins than for the dizygotic twins, the similarity indicates that the traits are not genetically independent and there is some common genetics influencing both IQ and brain volume. (Statistical power can be boosted by using siblings as well.^[50])

Genetic correlations are affected by methodological concerns; underestimation of heritability, such as due to assortative mating, will lead to overestimates of longitudinal genetic correlation,^[51] and moderate levels of misdiagnoses can create pseudo correlations.^[52] As they are affected by heritabilities of both traits, genetic correlations have low statistical power, especially in the presence of measurement errors biasing heritability downwards, because "estimates of genetic correlations are usually subject to rather large sampling errors and therefore seldom very precise": the standard error of an estimate $r_{g}$ is $\sigma (r_{g})={\frac {1-r_{g}^{2}}{\sqrt {2}}}\cdot {\sqrt {\frac {\sigma (h_{x}^{2})\cdot \sigma (h_{y}^{2})}{h_{x}^{2}\cdot h_{y}^{2}}}}$ .^[53] (Larger genetic correlations & heritabilities will be estimated more precisely.^[54]) However, inclusion of genetic correlations in an analysis of a pleiotropic trait can boost power for the same reason that multivariate regressions are more powerful than separate univariate regressions.^[55]

Twin methods have the advantage of being usable without detailed biological data, with human genetic correlations calculated as far back as the 1970s and animal/plant genetic correlations calculated in the 1930s, and require sample sizes in the hundreds for being well-powered, but they have the disadvantage of making assumptions which have been criticized, and in the case of rare traits like anorexia nervosa it may be difficult to find enough twins with a diagnosis to make meaningful cross-twin comparisons, and can only be estimated with access to the twin data; molecular genetic methods like GCTA or LD score regression have the advantage of not requiring specific degrees of relatedness and so can easily study rare traits using case-control designs, which also reduces the number of assumptions they rely on, but those methods could not be run until recently, require large sample sizes in the thousands or hundreds of thousands (to obtain precise SNP heritability estimates, see the standard error formula), may require individual-level genetic data (in the case of GCTA but not LD score regression)

Given a genetic covariance matrix, the genetic correlation is computed by standardizing this, i.e., by converting the covariance matrix to a correlation matrix. For example, if two traits, say height and weight have the following additive genetic variance-covariance matrix:

	Height	Weight
Height	36	36
Weight	36	117

Then the genetic correlation is .55, as seen is the standardized matrix below:

	Height	Weight
Height	1
Weight	.55	1

In practice, structural equation modeling applications such as Mx or OpenMx (and before that, historically, LISREL^[56]) are used to calculate both the genetic covariance matrix and its standardized form. In R, cov2cor() will standardize the matrix.

Typically, published reports will provide genetic variance components that have been standardized as a proportion of total variance (for instance in an ACE twin study model standardised as a proportion of V-total = A+C+E). In this case, the metric for computing the genetic covariance (the variance within the genetic covariance matrix) is lost (because of the standardizing process), so you cannot readily estimate the genetic correlation of two traits from such published models. Multivariate models (such as the Cholesky decomposition^{[better source needed]}) will, however, allow the viewer to see shared genetic effects (as opposed to the genetic correlation) by following path rules. It is important therefore to provide the unstandardised path coefficients in publications.

Correlations

Human correlations

Genetic correlations have been measured for a wide variety of human traits.

Anthropometric

facial averageness/attractiveness^[57]
baldness^[58]
tiredness/forced expiratory volume^[59]
tiredness/grip strength^[59]
tiredness/self-rated health^[59]
tiredness/longevity^[59]
self-reported health/longevity^[60]
life satisfaction/positive affect^[61]
exercise/longevity^[62]
self-reported health/forced expiratory volume in one second (FEV1)^[60]
tiredness/obesity^[59]
tiredness/BMI^[59]
baseline BMI/increase in BMI^[63]
chronotype/BMI^[64]
undersleeping/BMI^[64]
oversleeping/BMI^[64]
morning chronotype/BMI^[65]
difficulty sleeping/BMI^[65]
difficulty sleeping/waist circumference^[65]
difficulty sleeping/waist-hip ratio^[65]
difficulty sleeping/neck bone mineral density^[65]
daytime sleepiness/BMI^[65]
daytime sleepiness/self-reported sleep duration^[65]
daytime sleepiness/difficulty sleeping^[65]
daytime sleepiness/waist circumference^[65]
daytime sleepiness/waist-hip ratio^[65]
sex/sleep pattern^[66]
sex/sleep quality^[66]
self-reported sleep duration/birth weight^[65]
self-reported sleep duration/difficulty sleeping^[65]
self-reported sleep duration/neck bone mineral density^[65]
difficulty sleeping/birth weight^[65]
breast size/BMI^[67]
sweet taste perception/BMI^[68]
tiredness/waist-hip ratio^[59]
self-reported health/BMI^[60]
early puberty/BMI^[69]
age at first sex/BMI^[70]
exercise/BMI^[71]
exercise/waist circumference^[71]
body fat percentage/cardiorespiratory fitness (VO2max)^[72]
BMI/waist circumference^[71]
waist-hip ratio/BMI^[73]
fasting insulin/BMI^[73]
fasting glucose/waist-hip ratio^[73]
heart rate recovery/vagal rebound^[74]
longevity/resting heart rate^[75]
exercise/resting heart rate^[74]^[76]
exercise/heart rate recovery^[74]
exercise/respiratory sinus arrhythmia^[76]
ambulatory heart period/respiratory sinus arrhythmia^[77]
respiration rate/respiratory sinus arrhythmia^[77]^[78]
weight/height^[79]
birth weight//infant head circumference^[80]
birth weight/birth length^[80]
birth weight/childhood height^[80]
birth weight/adult height^[80]
birth weight/waist circumference^[80]
birth weight/hip circumference^[80]
birth weight/BMI^[80]
birth weight/childhood obesity^[80]
birth weight/adult obesity^[80]
birth weight/pubertal growth^[80]
age at first sex/height^[70]
age at first sex/birth weight^[70]
age at first sex/birth length^[70]
early puberty/age at first sex^[70]
early puberty/age at first birth^[70]
age at first sex/age at first birth^[70]
age at first sex/age at menarche^[70]
age at first sex/age at voice breaking^[70]
age at first sex/age at menopause^[70]
age at first sex/number of sexual partners^[70]
age at first sex/number of children ever born^[70]
age at first sex/childless^[70]
age at first sex/happiness^[70]
age at first birth/age at menarche^[81]
age at first birth/age at menopause^[81]
age at first birth/voice breaking^[81]
age at first birth/polycystic ovary syndrome^[81]
age at first birth/age at first sexual intercourse^[81]
age at first birth/birth weight^[81]
age at first birth/years of education^[81]
age at first birth/cigarettes per day^[81]
age at first birth/ever smoked^[81]
age at first birth/age onset of smoking^[81]
age at first birth/triglycerides^[81]
age at first birth/type 2 diabetes^[81]
age at first birth/fasting insulin level^[81]
age at first birth/waist-hip ratio^[81]
age at first birth/BMI^[81]
age at first birth/height^[81]
number of children ever born/age at first sexual intercourse^[81]
number of children ever born/years of education^[81]
anthropometric measurements made on the 6 major sub-populations of the Solomon Islands (Harvard Solomon Islands Project)^[82]
- weight
- sitting height
- height
- biacromial diameter
- bicristal diameter (biiliac breadth)
- chest breadth
- foot length
- total facial height
- upper facial height
- nose length
- nose breadth
- bicondylar humerus diameter
- wrist breadth
- hand breadth
- hand length
- bicondylar femur diameter
- foot breadth
- head length
- head breadth
- minimum frontal diameter
- bizygomatic diameter
- bigonial diameter
- head circumference
- upper arm circumference
- calf circumference
- triceps skinfold thickness
- subscapular skinfold thickness
intracranial volume/height^[83]
intracranial volume/child head circumference^[83]
intracranial volume/birth length^[83]
intracranial volume/birth weight^[83]
head motion/BMI^[84]
head motion/waist circumference^[84]
head motion/hypertension^[84]
head motion/monetary delay temporal discounting^[84]

Neuroanatomical

correlations between left/right hemisphere volume, volumes/thicknesses of individual regions, white matter connectivity, correlation between volume/thickness and cognitive performance on WM/IQ tests etc, stability of brain regions over time due to stable genetics^[85]^[86]^[87]^[88]^[89]^[90]^[91]^[92]^[54]^[93]^[94]^[95]^[96]^[97]^[98]^[99]^[100]^[101]^[102]^[103]^[104]^[105]^[106]^[107]^[108]^[109]^[110] (see also brain size and intelligence)^[111]
epigenetic age acceleration/diffuse plaque^[112]
epigenetic age acceleration/neuritic plaque^[112]
epigenetic age acceleration/working memory^[112]
brain atrophy/blood pulse pressure^[113]
subcortical abnormal white matter/ependymal white matter^[114]
abnormal white matter/systolic blood pressure^[115]^[116]^[117]
Eyes Test empathy score/volume of the caudate nucleus^[118]
Eyes Test empathy score/volume of the putamen^[118]
head motion/default mode network connectivity^[119]

Intelligence

intelligence longitudinal stability and consistency ^[31]^[51]^[120]^[121]^[122]^[123]^[124]
cognitive performance & neuroanatomical properties^[85]^[88]^[91]^[92]^[94]^[99]^[101]^[111]
behavioral/emotional problems in children^[125]
intelligence/reading^[126]^[127]
intelligence/longevity^[128]
tiredness/verbal-numerical reasoning ^[59]
self-reported health/intelligence^[60]
age at first sex/intelligence^[70]
intelligence/Openness^[129]
intelligence/Conscientiousness^[129]^[130]
intelligence/SES^[14]^[131]
Coronary artery disease/verbal-numerical reasoning^[13]
Stroke: ischaemic/verbal-numerical reasoning^[13]
Stroke: cardioembolic/verbal-numerical reasoning^[13]
Stroke: large vessel disease/verbal-numerical reasoning^[13]
Stroke: small vessel disease/verbal-numerical reasoning^[13]
Type 2 diabetes/verbal-numerical reasoning^[13]
ADHD/verbal-numerical reasoning^[13]^[132]
ADHD/IQ^[133]
Alzheimer's disease/verbal-numerical reasoning^[13]
Autism/verbal-numerical reasoning^[13]^[134]
Bipolar disorder/verbal-numerical reasoning^[13]
Major depressive disorder/verbal-numerical reasoning^[13]
Schizophrenia/verbal-numerical reasoning^[13]
intelligence/temperament^[135]^[136]
Hippocampal volume/verbal-numerical reasoning^[13]
Intracranial volume (ICV)/verbal-numerical reasoning^[13]
intracranial volume/childhood cognitive function^[83]
intracranial volume/adult cognitive function^[83]
Infant head circumference/verbal-numerical reasoning^[13]
Blood pressure: diastolic/verbal-numerical reasoning^[13]
Blood pressure: systolic/verbal-numerical reasoning^[13]
BMI/verbal-numerical reasoning^[13]
intelligence/weight^[79]
Height/verbal-numerical reasoning^[13]
intelligence/height^[79]^[137]^[138]^[139]^[140]^[141]
Longevity/verbal-numerical reasoning^[13]
Forced expiratory volume in 1 s (FEV1)/verbal-numerical reasoning^[13]
Childhood cognitive ability/verbal-numerical reasoning^[13]
Coronary artery disease/reaction time^[13]
Stroke: ischaemic/reaction time^[13]
Stroke: cardioembolic/reaction time^[13]
Stroke: large vessel disease/reaction time^[13]
Stroke: small vessel disease/reaction time^[13]
Type 2 diabetes/reaction time^[13]
ADHD/reaction time^[13]^[132]
Alzheimer's disease/reaction time^[13]
Autism/reaction time^[13]
Bipolar disorder/reaction time^[13]
Major depressive disorder/reaction time^[13]
Schizophrenia/reaction time^[13]
Hippocampal volume/reaction time^[13]
Intracranial volume/reaction time^[13]
Infant head circumference/reaction time^[13]
Blood pressure: diastolic/reaction time^[13]
Blood pressure: systolic/reaction time^[13]
BMI/reaction time^[13]
Height/reaction time^[13]
Longevity/reaction time^[13]
Forced expiratory volume in 1 s (FEV1)/reaction time^[13]
Childhood cognitive ability/reaction time^[13]
Coronary artery disease/memory^[13]
Stroke: ischaemic/memory^[13]
Stroke: cardioembolic/memory^[13]
Stroke: large vessel disease/memory^[13]
Stroke: small vessel disease/memory^[13]
Type 2 diabetes/memory^[13]
ADHD/memory^[13]
Alzheimer's disease/memory^[13]
Autism/memory^[13]
Bipolar disorder/memory^[13]
Major depressive disorder/memory^[13]
Schizophrenia/memory^[13]
Hippocampal volume/memory^[13]
Intracranial volume/memory^[13]
Infant head circumference/memory^[13]
Blood pressure: diastolic/memory^[13]
Blood pressure: systolic/memory^[13]
BMI/memory^[13]
Height/memory^[13]
Longevity/memory^[13]
Forced expiratory volume in 1 s (FEV1)/memory^[13]
Childhood cognitive ability/memory^[13]
go-no-go/fast task reaction time^[132]
intelligence/reaction-time variability^[132]
intelligence/reaction-time^[132]
reaction-time variability/ADHD^[132]^[142]^[143]^[144]^[145]
reaction-time/reaction-time variability^[132]
frequency of talking or texting on smartphone/intelligence^[146]

Education

education longitudinal stability^[147]^[148]
education/family SES^[27]^[149]
education/SES^[131]^[149]^[150]^[151]
education/wealth^[149]
education/income^[149]^[152]
education/welfare^[149]
education/credit scores^[149]
education/social mobility^[149]
education/working overseas^[149]
education/financial literacy or difficulties^[149]
age at first sex/years of education^[70]
health/education^[9]^[153]
birth weight/education^[80]
self-reported health/education^[60]^[154]
education/self-efficacy^[155]
- self-efficacy/GCSE scores^[156]
child-rated school environment/GCSE scores^[156]
education/personality^[157]
- personality/GCSE scores^[156]^[158]
- education/Openness^[129]^[159]
- education/Conscientiousness^[129]^[130]^[159]
- education/motivation^[160]^[161]
- education/Neuroticism^[159]^[162]
- education/Extraversion^[159]
- sex-specific personality effects (Aggression/Achievement Striving/Self-Control) on education^[163]
well-being/GCSE scores^[156]
education/behavioral problems^[164]^[165]^[166]^[167]
- parent-rated behavior problems/GCSE scores^[156]
- child-rated behavior problems/GCSE scores^[156]
independent reading/reading ability and stability^[149]^[168]
book exposure/reading ability^[169]
reading fluency/reading comprehension^[170]
Coronary artery disease/educational attainment^[13]
Stroke: ischaemic/educational attainment^[13]
Stroke: cardioembolic/educational attainment^[13]
Stroke: large vessel disease/educational attainment^[13]
Stroke: small vessel disease/educational attainment^[13]
Type 2 diabetes/educational attainment^[13]
ADHD/educational attainment^[13]
- ADHD/GCSE exam scores^[133]
- ADHD/Key Stage 3 exam scores^[133]
- ADHD/Key Stage 5 taking^[133]
Alzheimer's disease/educational attainment^[13]^[162]
Autism/educational attainment^[13]^[171]
Bipolar disorder/educational attainment^[13]^[162]
Major depressive disorder/educational attainment^[13]^[154]
Schizophrenia/educational attainment^[13]^[162]
Blood pressure: diastolic/educational attainment^[13]
Blood pressure: systolic/educational attainment^[13]
BMI/educational attainment^[13]^[154]
waist circumference/education^[172]
education/back pain^[173]
Height/educational attainment^[13]^[162]^[174]
Longevity/educational attainment^[13]^[175]
Forced expiratory volume in 1 s (FEV1)/educational attainment^[13]
Years of education/educational attainment^[13]
College degree/educational attainment^[13]
evening chronotype/educational attainment^[65]
Years of education/verbal-numerical reasoning^[13]
Years of education/reaction time^[13]
Years of education/memory^[13]
Hippocampal volume/educational attainment^[13]
Intracranial volume/educational attainment^[13]^[162]
Infant head circumference/educational attainment^[13]
Childhood cognitive ability/educational attainment^[13]
College degree/memory^[13]
College degree/reaction time^[13]
College degree/verbal-numerical reasoning^[13]
intelligence/GCSE scores^[156]
grades or exam scores in various school subjects arts/sciences^[176]^[177]^[178]^[156]^[179]^[180]^[181]
educational subject preferences^[181]
education/developmental milestones (smiling, walking, talking, feeding oneself, daytime potty training, communicating using sentences, and night-time potty training)^[149]
education/intelligence^[34]^[79]^[129]^[130]^[131]^[135]^[147]^[149]^[150]^[151]^[162]^[164]^[177]^[180]^[182]^[183]^[184]^[185]^[186]^[187]^[188]^[189]^[190]^[191]^[192]^[193]
highest level of mathematics class/college completion^[194]
highest level of mathematics class/years of education^[194]
highest level of mathematics class/working in a technical occupation^[194]
carry a tune/highest level of mathematics class^[194]
Eyes Test empathy score/years of college^[118]
Eyes Test empathy score/years of education^[118]
Eyes Test empathy score/intelligence^[118]
Systemizing Quotient-Revised (SQ-R)/years of college^[195]
difficulty sleeping/years of education^[65]
education/home environment^[196]
education/school environment^[197]

Psychological

food fussiness/food neophobia^[198]
dental fear/fear of pain^[199]
carry a tune/clap to a beat^[194]
carry a tune/perfect pitch^[194]
carry a tune/sing back musical notes^[194]
phonological coding/pig Latin task^[200]
phonological coding/rhyme-generation^[200]
longitudinal stability of planning/behavioral disinhibition (Porteus Maze Test)^[201]

Psychiatric

intellectual disabilities^[202]^[203]^[204]^[205]^[206]^[207]
- reading/math disability^[177]^[178]^[191]^[208]^[209]^[210]
- reading difficulty/sex^[211]
- word recognition/phonological coding/orthographic coding in the reading disabled^[212]
psychiatric illnesses/property crime^[213]
schizophrenia/epilepsy^[214]
schizophrenia/bipolar disorder^[35]^[215]^[216]^[217]^[218]
schizophrenia/brain-volumes^[219]^[220]
schizophrenia/major depressive disorder^[217]
schizophrenia/autism^[217]
sleep/schizophrenia^[221]
tiredness/schizophrenia^[59]
self-reported health/schizophrenia^[60]
creativity/schizophrenia^[222]
age at first sex/schizophrenia^[70]
schizophrenia/HIV infection/risky sexual behavior^[223]
Empathy Quotient score/schizophrenia^[195]
self-reported sleep duration/schizophrenia^[224]
daytime sleepiness/schizophrenia^[65]
bipolar disorder/rheumatoid arthritis^[44]
bipolar disorder/type 2 diabetes^[44]
bipolar disorder/major depressive disorder^[217]
bipolar disorder/creativity^[222]
self-reported sleep duration/bipolar disorder^[65]
age at first sex/bipolar disorder^[70]
Empathy Quotient score/bipolar disorder^[195]
Systemizing Quotient-Revised (SQ-R)/bipolar disorder^[195]
brain region activation/bipolar disorder^[225]
tiredness/ADHD^[59]
major depressive disorder/ADHD^[217]
self-reported health/ADHD^[60]
autism/ADHD^[226]
age at first sex/autism^[70]
Empathy Quotient score/autism^[195]
Systemizing Quotient-Revised (SQ-R)/autism^[195]
age at first sex/ADHD^[70]
ADHD/tics^[227]
ADHD/obsessive-compulsive^[227]^[228]
intracranial volume/ADHD^[220]
ADHD/bipolar disorder^[229]
tiredness/bipolar disorder^[59]
tiredness/major depressive disorder^[59]
daytime sleepiness/major depressive disorder^[65]
difficulty sleeping/major depressive disorder^[65]
self-reported health/major depressive disorder^[60]
schizophrenia/major depressive disorder^[230]
bipolar disorder/major depressive disorder^[230]
age at first sex/major depressive disorder^[70]
migraine/Neuroticism^[231]
tiredness/Neuroticism^[59]
self-reported health/Neuroticism^[60]
Grit/Conscientiousness^[158]
Conscientiousness/Extraversion^[232]
Neuroticism/Extraversion^[159]^[232]
Openness/Extraversion^[159]^[232]
Extraversion: sociability and impulsiveness facets^[233]
frequency of talking or texting on smartphone/Extraversion^[146]
Neuroticism/Conscientiousness^[159]^[232]
Openness/Conscientiousness^[232]
Openness/Neuroticism^[232]
Eyes Test empathy score/Openness^[118]
Eyes Test empathy score/self-reported empathy (Empathy Quotient)^[118]
Neuroticism, extraversion, psychoticism, social attitudes scale, Wilson conservatism scale longitudinal stability^[6]
Neuroticism/loneliness^[234]
extraversion/loneliness^[234]
depression symptoms/loneliness^[234]
behavioral/emotional problems in children^[125]^[235]^[236]^[237]^[238]
antisocial behavior/Extraversion^[239]
antisocial behavior/Agreeableness^[239]
antisocial behavior/Conscientiousness^[239]
antisocial behavior/sensation seeking^[239]
antisocial behavior/urgency^[239]
antisocial behavior/lack of premeditation^[239]
antisocial behavior/lack of perseverance^[239]
antisocial behavior/Psychoticism^[239]
antisocial behavior/novelty seeking^[239]
antisocial behavior/impulsivity^[239]
antisocial behavior/reward dependence^[239]
antisocial behavior/depressive symptoms^[240]
longitudinal stability of antisocial symptoms^[240]
longitudinal stability of depressive symptoms^[240]
unipolar/bipolar depression^[241]
age at first sex/Alzheimers^[70]
age at first sex/risk-taking propensity^[70]
age at first sex/suffer from nerves^[70]
age at first sex/irritable personality^[70]
self-reported health/anorexia nervosa^[60]
age at first sex/anorexia nervosa^[70]
obsessive-compulsive disorder/anorexia nervosa^[242]
Eyes Test empathy score/anorexia nervosa^[118]
Empathy Quotient score/anorexia nervosa^[195]
Systemizing Quotient-Revised (SQ-R)/anorexia nervosa^[195]
Tourette syndrome/obsessive-compulsive disorder^[228]^[243]^[244]
hoarding/obsessive-compulsive syndrome^[245]^[246]
obsessive-compulsive disorder inventory/inventory subscales (checking, hoarding, obsessing, ordering, and washing)^[247]^[248]
excessive object acquisition/difficulties discarding possessions^[249]
compulsive hoarding/tics^[245]
obsessive-compulsive syndrome/tics^[227]^[245]
panic disorder/generalised anxiety disorder/phobias/obsessive-compulsive disorder/post-traumatic stress disorder^[250]^[251]^[252]
bulimia/anorexia nervosa^[253]
Right temporal pole surface area/anorexia nervosa^[220]
weight and shape concerns and behaviors/binge eating^[254]
obesity/binge eating^[255]
purging/binge eating^[256]
body dissatisfaction / weight preoccupation / binge eating^[257]
major depressive disorder/anorexia nervosa^[258]
Neuroticism/anorexia nervosa^[259]
Schizophrenia/anorexia nervosa^[259]
Psychiatric factor/anorexia nervosa^[259]
Years of education/anorexia nervosa^[259]
College attendance/anorexia nervosa^[259]
Extreme BMI/anorexia nervosa^[259]
Body fat percentage/anorexia nervosa^[259]
Overweight/anorexia nervosa^[259]
Hip circumference/anorexia nervosa^[259]
HDL cholesterol/anorexia nervosa^[259]
Phospholipids in large HDL/anorexia nervosa^[259]
Concentration of large HDL particles/anorexia nervosa^[259]
Total lipids in large HDL/anorexia nervosa^[259]
Cholesterol esters in large HDL/anorexia nervosa^[259]
Free cholesterol in large HDL/anorexia nervosa^[259]
Total cholesterol in large HDL/anorexia nervosa^[259]
Fasting glucose/anorexia nervosa^[259]
HOMA-Beta/anorexia nervosa^[259]
Fasting insulin/anorexia nervosa^[259]
HOMA-IR/anorexia nervosa^[259]
major depressive disorder/bulimia^[260]
Right temporal pole surface area/major depressive disorder^[220]
dementia with Lewy bodies/Alzheimers^[261]
dementia with Lewy bodies/Parkinson's^[261]
Alzheimers/Parkinson's^[261]
difficulty sleeping/Alzheimer's disease^[65]
intracranial volume/Parkinson's disease^[83]
autism/Social and Communication Disorders Checklist^[134]
childhood sexual abuse/age at first sex^[262]
stressful life-events/psychotic events^[263]
Subjective well-being / depressive symptoms^[61]
Subjective well-being / Neuroticism^[61]
Depressive symptoms / Neuroticism^[61]
menstrual symptoms/anxiety/depression/Neuroticism^[264]
life satisfaction/Neuroticism^[265]
positive affect/Neuroticism^[265]
Anxiety disorders / subjective well-being^[61]
Anxiety disorders / Neuroticism^[61]
Anxiety disorders / depressive symptoms^[61]
Autism spectrum disorder / subjective well-being^[61]
Autism spectrum disorder / Neuroticism^[61]
intracranial volume/autism spectrum disorder^[220]
Bipolar disorder / subjective well-being^[61]
Bipolar disorder / Neuroticism^[61]
Bipolar disorder / depressive symptoms^[61]
Schizophrenia / subjective well-being^[61]
Schizophrenia / Neuroticism^[61]
Schizophrenia / depressive symptoms^[61]
BMI / depressive symptoms^[61]
Coronary artery disease / depressive symptoms^[61]
Coronary artery disease/Neuroticism^[61]
general anxiety disorder/major depressive disorder^[266]^[267]^[268]^[269]^[270]^[271]^[272]
burnout/major depressive order^[271]
burnout/general anxiety disorder^[271]
major depressive disorder/phobias (agoraphobia / social / animal / situational phobia)^[273]
phobias/panic disorder/bulimia nervosa^[272]^[274]^[275]^[276]^[277]^[278]^[279]

Drug use

lifetime use of marijuana/tobacco^[280]
tiredness/smoking status^[59]
sugar consumption/drug use^[281]
age at first sex/ever-smoker^[70]
age at first sex/cigarettes per day^[70]
self-reported sleep duration/cigarettes per day^[65]
difficulty sleeping/cigarettes per day^[65]
daytime sleepiness/cigarettes per day^[65]
age at first sex/smoking at onset^[70]
age at first sex/alcohol consumption^[70]
alcohol consumption/ventral striatum activity/ADHD^[282]
Ever-smoker / subjective well-being^[61]
Ever-smoker / neuroticism^[61]
Ever-smoker / depressive symptoms^[61]
Smoking/education^[283]
alcohol drinking/education^[283]
alcohol effects on arithmetic performance / alcohol effects on motor coordination^[284]
willingness to drive drunk/Eysenck personality scales^[285]

Biological

tiredness/HDL cholesterol^[59]
tiredness/HbA1c^[59]
tiredness/triglycerides^[59]
self-reported health/systolic and diastolic blood pressure^[60]
birth weight/diastolic blood pressure^[80]
birth weight/systolic blood pressure^[80]
birth weight/total cholesterol^[80]
birth weight/HDL cholesterol^[80]
birth weight/LDL cholesterol^[80]
Triglycerides / subjective well-being^[61]
Triglycerides / neuroticism^[61]
Triglycerides / depressive symptoms^[61]
fasting insulin/triglycerides^[73]
fasting glucose/fasting triglycerides^[73]
waist-hip ratio/fasting triglycerides^[73]
fasting triglycerides/BMI^[73]
HDL/triglycerides^[73]
early puberty/fasting insulin^[69]
early puberty/lipid profiles^[69]
early puberty/bone mineral density^[69]
age at first sex/femoral neck bone mineral density^[70]
age at first sex/lumbar spine bone mineral density^[70]
age at first sex/fasting glucose^[70]
age at first sex/HDL cholesterol^[70]
age at first sex/LDL cholesterol^[70]
age at first sex/total cholesterol^[70]
age at first sex/triglycerides^[70]
age at first sex/fasting insulin^[70]
age at first sex/HbA1C^[70]
age at first sex/diastolic blood pressure^[70]
age at first sex/systolic blood pressure^[70]
fasting HDL/BMI^[73]
systolic blood pressure/BMI^[73]
waist-hip ratio/fasting glucose^[73]
waist-hip ratio/fasting insulin^[73]
waist-hip ratio/HDL^[73]
waist-hip ratio/systolic blood pressure^[73]
fasting glucose/fasting insulin^[73]
fasting glucose/HDL^[73]
fasting glucose/systolic blood pressure^[73]
fasting insulin/HDL^[73]
fasting insulin/systolic blood pressure^[73]
HDL/systolic blood pressure^[73]
liver enzymes/total cholesterol^[19]
liver enzymes/LDL cholesterol^[19]
liver enzymes/HDL cholesterol^[19]
liver enzymes/triglycerides^[19]
liver enzymes/glucose^[19]
liver enzymes/insulin^[19]
liver enzymes/HOMA-B^[19]
liver enzymes/HOMA-IR^[19]
liver enzymes/c-reactive protein^[19]
liver enzymes/alcohol consumption^[19]

Disease

immune disorders^[18]^[286]^[287]^[288]
tiredness/type 2 diabetes^[59]
sleep/type 2 diabetes^[221]
Type 2 diabetes/hypertension^[44]^[46]
rheumatoid arthritis/hypertension^[44]
psoriasis/type 2 diabetes^[289]
birth weight/type 2 diabetes^[80]
birth weight/2 hour glucose response^[80]
birth weight/fasting insulin^[80]
birth weight/Hb1Ac^[80]
difficulty sleeping/type 2 diabetes^[65]
oversleeping/type 2 diabetes^[64]
difficulty sleeping/fasting insulin^[65]
difficulty sleeping/fasting glucose^[65]
daytime sleepiness/HOMA-IR^[65]
daytime sleepiness/fasting insulin^[65]
difficulty sleeping/HOMA-IR^[65]
psoriasis/BMI^[289]
self-reported health/coronary artery disease^[60]
triglycerides/coronary artery disease^[290]^[291]^[292]
birth weight/coronary artery disease^[80]
self-reported health/ischaemic stroke^[60]
C-reactive protein/ischemic vascular disease^[293]
coronary artery disease/LDL^[291]^[292]
coronary artery disease/HDL^[291]
coronary artery disease/BMI^[291]
coronary artery disease/systolic blood pressure^[291]
coronary artery disease/type 1 diabetes^[291]
daytime sleepiness/coronary artery disease^[65]
difficulty sleeping/coronary artery disease^[65]
coronary artery calcification (CAC)/coronary artery disease^[292]
Lp(a)/coronary artery disease^[292]
LP-PLA2 activity/coronary artery disease^[292]
carotid plaque/coronary artery disease^[292]
vWF/coronary artery disease^[292]
FVIII/coronary artery disease^[292]
height/coronary artery disease^[292]
self-reported health/type 2 diabetes^[60]
rheumatoid arthritis/lupus^[294]^[295]
early puberty/type 2 diabetes^[69]
early puberty/cardiovascular disease^[69]
early puberty/polycystic ovary syndrome^[69]
age at first sex/rheumatoid arthritis^[70]
age at first sex/ulcerative colitis^[70]
age at first sex/Crohn's disease^[70]
Crohn's disease/ulcerative colitis^[296]^[297]
self-reported sleep duration/Crohn's disease^[65]
difficulty sleeping/Crohn's disease^[65]
age at first sex/cardiovascular disease^[70]
age at first sex/type 2 diabetes^[70]
type 2 diabetes/Dyslipidemia^[46]
type 2 diabetes/osteoarthritis^[46]
type 2 diabetes/osteoporosis^[46]
asthma/type 2 diabetes^[46]
cardiovascular disease/type 2 diabetes^[46]
esophageal adenocarcinoma/Barrett's esophagus^[298]
Intracranial aneurysms/abdominal aortic aneurysms/thoracic aortic aneurysms^[299]
Allergic rhinitis/asthma^[46]
Allergic rhinitis/hypertension^[46]
Allergic rhinitis/osteoarthritis^[46]
asthma/cardiovascular disease^[46]
asthma/Dyslipidemia^[46]
asthma/hypertension^[46]
asthma/osteoarthritis^[46]
cardiovascular disease/Dyslipidemia^[46]
cardiovascular disease/hypertension^[46]
cardiovascular disease/osteoarthritis^[46]

Transfer

Trans-population

schizophrenia^[300]
gene expression^[301]
rheumatoid arthritis^[301]
type 2 diabetes^[301]

Trans-cohort

depressive symptoms: GERA/PGC,^[61] GERA/UKB,^[61] UKB/PGC^[61]
neuroticism: UK Biobank (UKB) / Genetics of Personality Consortium^[61]
autism: PGC (USA)/iPSYCH (Denmark)^[134]
male/female Empathy Quotient score^[195]
male/female Systemizing Quotient-Revised (SQ-R)^[195]
male/female Eyes Test empathy score^[118]
ARIC/EHR phenotype consistencies^[302]

Trans-method

custom immunochip (iChip) SNP array/standard SNP array (comparing their estimates for the Crohn's disease/ulcerative colitis genetic correlation)^[296]
major depressive order: Psychiatric Genomics Consortium (PGC) clinical depression diagnosis/23andMe self-report depression^[230]
major depressive disorder/self-declared depression^[303]
self-reported height/clinically measured height^[304]

Animal/plant

chimpanzee cognitive performance factors^[305]
egg color in cross vs pure bred chickens^[306]
Batrachochytrium dendrobatidis infection/development time in Bufo spinosus toad^[307]
Fraxinus excelsior infection by Hymenoscyphus fraxineus: severities of crown and collar symptoms^[308]
Mimulus guttatus^[309]^[310]^[311]
Chinook salmon^[312]
various rat/cattle/sheep^[313]/finch/amphipod/human/rhesus macaque^[314]/pig/inland garter snake/coastal garter snake^[11]
pigs^[315]
mice ^[11]^[316]^[317]
Eucalyptus melliodora foliage chemistry^[318]
male genital length/female brain size in Eastern mosquitofish^[319]
higher alcohol preference/greater fear potentiated startle in mice^[320]
biomass/yield per plant/straw yield in Paspalum scrobiculatum^[321]
sexual antagonism in Drosophila melanogaster]^[322]

References

^ Falconer 1960
^ Neale & Maes 1996, Methodology for genetics studies of twins and families (6th ed.). Dordrecht, The Netherlands: Kluwer.
^ ^a ^b pg 123 of Plomin 2012
^ pg194-195 of Jensen 1980, Bias in Mental Testing
^ Martin & Eaves 1977, "The Genetical Analysis of Covariance Structure"
^ ^a ^b Eaves et al 1978, "Model-fitting approaches to the analysis of human behaviour"
^ Loehlin & Vandenberg 1968, "Genetic and environmental components in the covariation of cognitive abilities: An additive model", in Progress in Human Behaviour Genetics, ed. S. G. Vandenberg, pp. 261278. Johns Hopkins, Baltimore.
^ Purcell 2002, "Variance components models for gene-environment interaction in twin analysis"
^ ^a ^b Kohler et al 2011, "Social Science Methods for Twins Data: Integrating Causality, Endowments and Heritability"
^ Wagner & Zhang 2011, "The pleiotropic structure of the genotype-phenotype map: The evolvability of complex organisms"
^ ^a ^b ^c Cheverud 1988, "A comparison of genetic and phenotypic correlations"
^ Krapohl et al 2015, "Phenome-wide analysis of genome-wide polygenic scores"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az ^ba ^bb ^bc ^bd ^be ^bf ^bg ^bh ^bi ^bj ^bk ^bl ^bm ^bn ^bo ^bp ^bq ^br ^bs ^bt ^bu ^bv ^bw ^bx ^by ^bz ^ca ^cb ^cc ^cd ^ce ^cf ^cg ^ch ^ci ^cj ^ck ^cl ^cm ^cn ^co ^cp ^cq ^cr ^cs Hagenaars et al 2016, "Shared genetic aetiology between cognitive functions and physical and mental health in UK Biobank (N=112 151) and 24 GWAS consortia"
^ ^a ^b ^c Hill et al 2016, "Molecular genetic contributions to social deprivation and household income in UK Biobank (n=112,151)"
^ ^a ^b "LD Hub: a centralized database and web interface to perform LD score regression that maximizes the potential of summary level GWAS data for SNP heritability and genetic correlation analysis", Zheng et al 2016
^ Sivakumaran et al 2011, "Abundant pleiotropy in human complex diseases and traits"
^ ^a ^b Solovieff et al 2013, "Pleiotropy in complex traits: challenges and strategies"
^ ^a ^b Cotsapas et al 2011, "Pervasive sharing of genetic effects in autoimmune disease"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Chambers et al 2011, "Genome-wide association study identifies loci influencing concentrations of liver enzymes in plasma"
^ Pickrell 2015, "Fulfilling the promise of Mendelian randomization"
^ Smith 2015, "Mendelian randomization: a premature burial?"; "Understanding Mendelian Randomization"
^ Burgess et al 2016, "Beyond Mendelian randomization: how to interpret evidence of shared genetic predictors"
^ Hagenaars et al 2016b, "Cognitive ability and physical health: a Mendelian randomization study"
^ Bowden et al 2015, "Mendelian randomization with invalid instruments: effect estimation and bias detection through Egger regression"
^ eg Falconer cites the example of chicken size and egg laying: chickens grown large for genetic reasons lay later, fewer, and larger eggs, while chickens grown large for environmental reasons lay quicker and more but normal sized eggs (pg315 of Falconer 1960); Falconer in Table 19.1 on pg316 also provides examples of opposite-signed phenotypic & genetic correlations: fleece-weight/length-of-wool & fleece weight/body-weight in sheep, and body-weight/egg-timing & body-weight/egg-production in chicken. One consequence of the negative chicken correlations was that, despite moderate heritabilities and a positive phenotypic correlation, selection had begun to fail to yield any improvements (pg329) according to "Genetic slippage in response to selection for multiple objectives", Dickerson 1955.
^ Kruuk, Loeske E. B.; Slate, Jon; Pemberton, Josephine M.; Brotherstone, Sue; Guinness, Fiona; Clutton-Brock, Tim (2002). "Antler Size in Red Deer: Heritability and Selection but No Evolution" (PDF). Evolution. 56 (8): 1683–95. doi:10.1111/j.0014-3820.2002.tb01480.x. PMID 12353761.
^ ^a ^b Krapohl & Plomin 2016, "Genetic link between family socioeconomic status and children's educational achievement estimated from genome-wide SNPs"
^ pg 397 of Plomin et al 2012
^ Munafo et al 2016, "Collider Scope: How selection bias can induce spurious associations"
^ Hewitt et al 1988, "Resolving the causes of developmental continuity or 'tracking.' I. Longitudinal twin studies during growth"
^ ^a ^b Deary et al 2012, "Genetic contributions to stability and change in intelligence from childhood to old age"
^ "The substantial comorbidity between specific cognitive disabilities is largely due to genetic factors, meaning that the same genes affect different learning disabilities although there are also disability-specific genes." pg184-185 of Plomin et al 2012
^ Rietveld et al 2013, "GWAS of 126,559 individuals identifies genetic variants associated with educational attainment"
^ ^a ^b Rietveld et al 2014, "Common genetic variants associated with cognitive performance identified using the proxy-phenotype method"
^ ^a ^b Andreassen et al 2013, "Improved Detection of Common Variants Associated with Schizophrenia and Bipolar Disorder Using Pleiotropy-Informed Conditional False Discovery Rate"
^ Hazel 1943, "The Genetic Basis for Constructing Selection Indexes"
^ Rae 1951, "The Importance of Genetic Correlations in Selection"
^ Hazel & Lush 1943, "The efficiency of three methods of selection"
^ Lerner 1950, Population genetics and animal improvement: as illustrated by the inheritance of egg production
^ Falconer 1960, pg324-329
^ Conner 2012, "Quantitative genetic approaches to evolutionary constraint: how useful?"
^ Beldade et al 2002, "Developmental constraints versus flexibility in morphological evolution"
^ Allen et al 2008, "Differences in the selection response of serially repeated color pattern characters: standing variation, development, and evolution"
^ ^a ^b ^c ^d ^e Lee et al 2012, "Estimation of pleiotropy between complex diseases using single-nucleotide polymorphism-derived genomic relationships and restricted maximum likelihood"
^ "LD Score regression distinguishes confounding from polygenicity in genome-wide association studies", Bulik-Sullivan et al 2015 (see also Shi et al 2016); LDSC
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q Loh et al 2015, "Contrasting regional architectures of schizophrenia and other complex diseases using fast variance components analysis"
^ Shi et al 2016, "Contrasting the genetic architecture of 30 complex traits from summary association data"
^ Lynch 2000, "Estimating genetic correlations in natural populations"
^ Golan et al 2014, "Measuring missing heritability: Inferring the contribution of common variants"
^ Posthuma & Boomsma 2000, "A note on the statistical power in extended twin designs"
^ ^a ^b DeFries et al 1987, "Genetic Stability of Cognitive Development From Childhood to Adulthood"
^ Wray et al 2012, "Impact of diagnostic misclassification on estimation of genetic correlations using genome-wide genotypes"
^ pg317-318 of Falconer 1960
^ ^a ^b Schmitt et al 2007b, "Review of twin and family studies on neuroanatomic phenotypes and typical neurodevelopment"
^ Almasy et al 1997, "Bivariate quantitative trait linkage analysis: pleiotropy versus co-incident linkages"
^ Heath et al 1989, "Testing structural equation models for twin data using LISREL"
^ Lee et al 2016, "Facial averageness and genetic quality: testing heritability, genetic correlation with attractiveness, and the paternal age effect"
^ Hagenaars et al 2016b, "Genetic Prediction of Male Pattern Baldness"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Deary et al 2016, "Genetic contributions to self-reported tiredness"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Harris et al 2015, "Molecular genetic contributions to self-rated health"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab Okbay et al 2016, "Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses"
^ Karvinen et al 2015, "Physical activity in adulthood: genes and mortality"
^ Hjelmborg et al 2008, "Genetic Influences on Growth Traits of BMI: A Longitudinal Study of Adult Twins"
^ ^a ^b ^c ^d Jones et al 2016, "Genome‐Wide Association Analyses in 128,266 Individuals Identifies New Morningness and Sleep Duration Loci"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah Lane et al 2016, "Genome-wide association analysis identifies novel loci for chronotype in 100,420 individuals from the UK Biobank"
^ ^a ^b Heath et al 1990, "Evidence for Genetic Influences on Sleep Disturbance and Sleep Pattern in Twins"
^ Wade et 2010, "Body mass index and breast size in women: same or different genes?"
^ Hwang et al 2016, "Sweet Taste Perception is Associated with Body Mass Index at the Phenotypic and Genotypic Level"
^ ^a ^b ^c ^d ^e ^f ^g Day et al 2015, "Genetic determinants of puberty timing in men and women: shared genetic aetiology between sexes and with health-related outcomes"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at Day et al 2016, "Physical and neurobehavioral determinants of reproductive onset and success"
^ ^a ^b ^c Mustelin et al 2009, "Physical activity reduces the influence of genetic effects on BMI and waist circumference: a study in young adult twins"
^ Schnurr et al 2016, "Genetic Correlation between Body Fat Percentage and Cardiorespiratory Fitness Suggests Common Genetic Etiology
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t Vattikuti et al 2012, "Heritability and Genetic Correlations Explained by Common SNPs for Metabolic Syndrome Traits"
^ ^a ^b ^c Nederend et al 2016, "Heritability of heart rate recovery and vagal rebound after exercise"
^ Eppinga et al 2016, "Identification of genomic loci associated with resting heart rate and shared genetic predictors with all-cause mortality"
^ ^a ^b de Geus et al 2003, "Genetic correlation of exercise with heart rate and respiratory sinus arrhythmia"
^ ^a ^b Kupper et al 2005, "A genetic analysis of ambulatory cardiorespiratory coupling"
^ Snieder et al 1997, "Heritability of respiratory sinus arrhythmia: Dependency on task and respiration rate"
^ ^a ^b ^c ^d Trzaskowski et al 2013, "DNA Evidence for Strong Genome-Wide Pleiotropy of Cognitive and Learning Abilities"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Horikoshi et al 2016, "Genome-wide associations for birth weight and correlations with adult disease"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Barban et al 2016, "Genome-wide analysis identifies 12 loci influencing human reproductive behavior" (supplement)
^ Black 1982, "Quantitative genetics of anthropometric variation in the Solomon Islands"
^ ^a ^b ^c ^d ^e ^f ^g "Novel genetic loci underlying human intracranial volume identified through genome-wide association", Adams et al 2016
^ ^a ^b ^c ^d Hodgson et al 2016, "Shared Genetic Factors Influence Head Motion During MRI and Body Mass Index"
^ ^a ^b Pennington et al 2000, "A twin MRI study of size variations in human brain"
^ Posthuma et al 2000, "Multivariate genetic analysis of brain structure in an extended twin design"
^ Baaré et al 2001, "Quantitative genetic modeling of variation in human brain morphology"
^ ^a ^b Posthuma et al 2002, "The association between brain volume and intelligence is of genetic origin"
^ Thompson et al 2002, "Mapping genetic influences on human brain structure"
^ Wright et al 2002, "Genetic contributions to regional variability in human brain structure: methods and preliminary results"
^ ^a ^b Carmelli et al 2002, "Quantitative genetic modeling of regional brain volumes and cognitive performance in older male twins"
^ ^a ^b Posthuma et al 2003, "Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed"
^ Pfefferbaum et al 2004, "Morphological changes in aging brain structures are differentially affected by time-linked environmental influences despite strong genetic stability"
^ ^a ^b Hulshoff Pol et al 2006, "Genetic contributions to human brain morphology and intelligence"
^ Peper et al 2007, "Genetic influences on human brain structure: a review of brain imaging studies in twins"
^ Schmitt et al 2007a, "A multivariate analysis of neuroanatomic relationships in a genetically informative pediatric sample"
^ Schmitt et al 2008, "Identification of genetically mediated cortical networks: a multivariate study of pediatric twins and siblings"
^ Panizzon et al 2009, "Distinct Genetic Influences on Cortical Surface Area and Cortical Thickness"
^ ^a ^b Chiang et al 2009, "Genetics of brain fiber architecture and intellectual performance"
^ Schmitt et al 2010, "A Twin Study of Intracerebral Volumetric Relationships"
^ ^a ^b Betjemann et al 2010, "Genetic Covariation Between Brain Volumes and IQ, Reading Performance, and Processing Speed"
^ Rimol et al, 2010, "Cortical thickness is influenced by regionally specific genetic factors"
^ Eyler et al, 2011, "Genetic patterns of correlation among subcortical volumes in humans: results from a magnetic resonance imaging twin study"
^ Chen et al 2011, "Genetic Influences on Cortical Regionalization in the Human Brain"
^ Chen et al 2012, "Hierarchical Genetic Organization of Human Cortical Surface Area"
^ Chen et al 2013, "Genetic topography of brain morphology"
^ Eyler et al 2014, "Conceptual and Data-based Investigation of Genetic Influences and Brain Asymmetry: A Twin Study of Multiple Structural Phenotypes"
^ Rentería et al 2014, "Genetic architecture of subcortical brain regions: common and region-specific genetic contributions"
^ Hibar et al 2015, "Common genetic variants influence human subcortical brain structures"
^ Wen et al 2016, "Distinct Genetic Influences on Cortical and Subcortical Brain Structures"
^ ^a ^b Shen et al 2016, "Heritability and genetic correlation between the cerebral cortex and associated white matter connections"
^ ^a ^b ^c Levine et al 2015, "Epigenetic age of the pre-frontal cortex is associated with neuritic plaques, amyloid load, and Alzheimer's disease related cognitive functioning"
^ Turner et al 2005, "Genomic Susceptibility Loci for Brain Atrophy in Hypertensive Sibships From the GENOA Study"
^ Kochunov et al 2009, "Analysis of genetic variability and whole genome linkage of whole-brain, subcortical and ependymal hyperintense white matter volume"
^ Kochunov et al 2010, "Whole brain and regional hyperintense white matter volume and blood pressure: overlap of genetic loci produced by bivariate, whole-genome linkage analyses"
^ Kochunov et al 2011, "Blood pressure and cerebral white matter share common genetic factors in Mexican Americans"
^ Fennema-Notestine et al 2016, "White matter disease in midlife is heritable, related to hypertension, and shares some genetic influence with systolic blood pressure"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ "Genome-wide meta-analysis of cognitive empathy: heritability, and correlates with sex, neuropsychiatric conditions and brain anatomy", Warrier et al 2016
^ Zhou et al 2016, "Genetic overlap between in-scanner head motion and the default network connectivity"
^ Plomin, R., DeFries, J. C, & McClearn, G. E. (1980). Behavioral genetics: A primer. San Francisco: Freeman.
^ Plomin & DeFries 1981 "Multivariate behavioral genetics and development: Twin studies". In L. Gedda, P. Parisi, & W. E. Nance (Eds.), Progress in clinical and biological research, Vol. 69B, Twin research 3: Intelligence, personality, and development (pp. 25-33). New York: Liss.
^ Plomin, R., & DeFries, J. C. (1985). Origins of individual differences in infancy: The Colorado Adoption Project. Orlando, FL: Academic Press
^ Bishop et al 2003, "Development genetic analysis of general cognitive ability from 1 to 12 years in a sample of adoptees, biological siblings, and twins"
^ Trzaskowski et al 2013, "DNA evidence for strong genetic stability and increasing heritability of intelligence from age 7 to 12"
^ ^a ^b "Single Nucleotide Polymorphism Heritability of a General Psychopathology Factor in Children", Neumann et al 2016
^ Brooks et al 1990, "Reading performance and general cognitive ability: A multivariate genetic analysis of twin data"
^ Cardon et al 1990, "Genetic correlations between reading performance and IQ in the Colorado Adoption Project"
^ Arden et al 2015, "The association between intelligence and lifespan is mostly genetic"
^ ^a ^b ^c ^d ^e Tucker-Drob et al 2016 , "Genetically-Mediated Associations Between Measures of Childhood Character and Academic Achievement"
^ ^a ^b ^c Luciano et al 2006, "The heritability of conscientiousness facets and their relationship to IQ and academic achievement"
^ ^a ^b ^c Marioni et al 2014, "Molecular genetic contributions to socioeconomic status and intelligence"
^ ^a ^b ^c ^d ^e ^f ^g Wood et al 2010, "Separation of genetic influences on attention deficit hyperactivity disorder symptoms and reaction time performance from those on IQ"
^ ^a ^b ^c ^d "Association between polygenic risk scores for attention-deficit hyperactivity disorder and educational and cognitive outcomes in the general population", Stergiakouli et al 2016
^ ^a ^b ^c Robinson et al 2016, "Genetic risk for autism spectrum disorders and neuropsychiatric variation in the general population"
^ ^a ^b Petrill & Thompson 1993, "The phenotypic and genetic relationships among measures of cognitive ability, temperament, and scholastic achievement"
^ Thompson et al 1988, "Multivariate analysis of cognitive and temperament measures in 24-month-old adoptive and nonadoptive sibling pairs"
^ Husén 1959, Psychological Twin Research
^ Sundet et al 2005, "Resolving the genetic and environmental sources of the correlation between height and intelligence: a study of nearly 2600 Norwegian male twin pairs"
^ Silventoinen et al 2006, "Genetic contributions to the association between height and intelligence: Evidence from Dutch twin data from childhood to middle age"
^ Beauchamp et al 2011, "On the sources of the height-intelligence correlation: new insights from a bivariate ACE model with assortative mating"
^ Keller et al 2013, "The genetic correlation between height and IQ: shared genes or assortative mating?"
^ Kuntsi & Stevenson 2001, "Psychological mechanisms in hyperactivity: II. The role of genetic factors"
^ Nigg et al 2004, "Evaluating the endophenotype model of ADHD neuropsychological deficit: results for parents and siblings of children with ADHD combined and inattentive subtypes"
^ Bidwell et al 2007, "Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder"
^ Luciano et al 2004a, "A genetic investigation of the covariation among inspection time, choice reaction time, and IQ subtest scores"
^ ^a ^b Miller et al 2012, "The heritability and genetic correlates of mobile phone use: a twin study of consumer behavior"
^ ^a ^b Johnson et al 2006, "Genetic and environmental influences on academic achievement trajectories during adolescence"
^ Baker et al 2006, "Genetics of Educational Attainment in Australian Twins: Sex Differences and Secular Changes"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Belsky et al 2016, "The genetics of success: How single-nucleotide polymorphisms associated with educational attainment relate to life-course development"
^ ^a ^b Tambs et al 1989, "Genetic and environmental contributions to the covariance between occupational status, educational attainment, and IQ: A study of twins"
^ ^a ^b Lichtenstein & Pedersen 1997, "Does genetic variance for cognitive abilities account for genetic variance in educational achievement and occupational status? A study of twins reared apart and twins reared together"
^ Behrman et al 1977, "Controlling for and measuring the effects of genetic and family environment in equations for schooling and labour market success", In Kinometrics, ed. P. Taubman. North Holland: Amsterdam
^ Johnson et al 2010, "Education reduces the effects of genetic susceptibilities to poor physical health"
^ ^a ^b ^c Boardman et al 2015, "What can genes tell us about the relationship between education and health?"
^ Greven et al 2009, "More than just IQ: school achievement is predicted by self-perceived abilities - but for genetic rather than environmental reasons"
^ ^a ^b ^c ^d ^e ^f ^g ^h Krapohl et al 2014, "The high heritability of educational achievement reflects many genetically influenced traits, not just intelligence"
^ Hicks et al 2008, "Moderating effects of personality on the genetic and environmental influences of school grades helps to explain sex differences in scholastic achievement"
^ ^a ^b Rimfeld et al 2016, "True grit and genetics: Predicting academic achievement from personality"
^ ^a ^b ^c ^d ^e ^f ^g "Educational attainment and personality are genetically intertwined", Mottus et al 2016
^ Gottschling et al 2012, "The prediction of school achievement from a behavior genetic perspective: Results from the German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS)"
^ Spinath et al 2008, "The nature and nurture of intelligence and motivation in the origins of sex differences in elementary school achievement"
^ ^a ^b ^c ^d ^e ^f ^g Okbay et al 2016, "Genome-wide association study identifies 74 loci associated with educational attainment"
^ Hicks et al 2008, "Moderating effects of personality on the genetic and environmental influences of school grades helps to explain sex differences in scholastic achievement"
^ ^a ^b Johnson et al 2005, "Disruptive behavior and school grades: Genetic and environmental relations in 11-year-olds"
^ Newsome et al 2014, "Genetic and environmental influences on the co-occurrence of early academic achievement and externalizing behavior"
^ Polderman et al 2010, "A systematic review of prospective studies on attention problems and academic achievement"
^ Saudino & Plomin 2007, "Why are hyperactivity and academic achievement related?"
^ Harlaar et al 2011, "Associations between reading achievement and independent reading in early elementary school: A genetically-informative cross-lagged study"
^ Harlaar et al 2007, "Reading exposure: a (largely) environmental risk factor with environmentally-mediated effects on reading performance in the primary school years"
^ Little et al 2016, "Exploring the Co-Development of Reading Fluency and Reading Comprehension: A Twin Study"
^ Weiner et al 2016, "Polygenic transmission disequilibrium confirms that common and rare variation act additively to create risk for autism spectrum disorders"
^ Vermeiren et al 2012, "Do genetic factors contribute to the relation between education and metabolic risk factors in young adults? A twin study"
^ Zadro et al 2016, "Does educational attainment increase the risk of low back pain when genetics is considered? A population based study of Spanish twins"
^ Silventoinen et al 2004, "Heritability of body height and educational attainment in an international context: comparison of adult twins in Minnesota and Finland"
^ Marioni et al 2016, "Genetic variants linked to education predict longevity"
^ Gill et al 1985, "Further evidence for genetic influences on educational achievement"
^ ^a ^b ^c Kovas et al 2007, "The genetic and environmental origins of learning abilities and disabilities in the early school years"
^ ^a ^b Markowitz et al 2005, "The etiology of mathematical and reading (dis)ability covariation in a sample of Dutch twins"
^ Davis et al 2014, "The correlation between reading and mathematics ability at age twelve has a substantial genetic component"
^ ^a ^b Rimfeld et al 2015, "Pleiotropy across academic subjects at the end of compulsory education"
^ ^a ^b Rimfeld et al 2016, "Genetics affects choice of academic subjects as well as achievement"
^ Martin 1975, "The inheritance of scholastic abilities in a sample of twins. II. Genetical analysis of examination results"
^ Bartels et al 2002, "Heritability of educational achievement in 12-year-olds and the overlap with cognitive ability"
^ Calvin et al 2012, "Multivariate genetic analyses of cognition and academic achievement from two population samples of 174,000 and 166,000 school children"
^ Johnson et al 2009, "Genetic and environmental transactions underlying educational attainment"
^ Wainwright et al 2005a, "The genetic basis of academic achievement on the Queensland Core Skills Test and its shared genetic variance with IQ"; Wainwright et al 2005b, "Multivariate Genetic Analysis of Academic Skills of the Queensland Core Skills Test and IQ Highlight the Importance of Genetic g"
^ Chambers 2000, "Academic achievement and IQ: A longitudinal genetic analysis" (as cited in Wainwright et al 2005)
^ Petrill & Wilkerson 2000, "Intelligence and achievement: A behavioral genetic perspective"
^ Thompson et al 1991, "Associations between cognitive abilities and scholastic achievement: Genetic overlap but environmental differences"
^ Wadsworth et al 1995b, "Cognitive ability and academic achievement in the Colorado Adoption Project: A multivariate genetic analysis of parent-offspring and sibling data"
^ ^a ^b Gillis et al 1993, Comorbidity of Reading and Mathematics Disabilities: Genetic and Environmental Etiologies
^ Wadsworth, S. J. (1994). "School achievement". In J. C. DeFries, R. Plomin, and D. W. Fulker (eds.), Nature and Nurture During Middle Childhood, Blackwell, Oxford
^ Wadsworth et al 1995a, "Covariation among measures of cognitive ability and academic achievement in the Colorado Adoption Project: Sibling analysis"
^ ^a ^b ^c ^d ^e ^f ^g Bell et al 2016, "PgmNr 430: GWASs of ability to carry a musical tune and mathematical educational attainment"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Genome-wide analyses of empathy and systemizing: heritability and correlates with sex, education, and psychiatric risk", Warrier et al 2016
^ Hanscombe et al 2011, "Chaotic homes and school achievement: A twin study"
^ Haworth et al 2013, "Understanding the science-learning environment: A genetically sensitive approach"
^ Smith et al 2016, "Food fussiness and food neophobia share a common etiology in early childhood"
^ Randall et al 2016, "Toward a genetic understanding of dental fear: evidence of heritability"
^ ^a ^b Olson et al 1989, "Specific deficits in component reading and language skills: Genetic and environmental influences", Journal of Learning Disabilities
^ Tuvblad et al 2016, "Heritability and Longitudinal Stability of Planning and Behavioral Disinhibition Based on the Porteus Maze Test"
^ Haworth et al 2009, "Generalist Genes and High Cognitive Abilities"
^ Andrews et al 2009, "Neurodevelopmental disorders: Cluster 2 of the proposed meta-structure for DSM-V and ICD-11"
^ Docherty, Kovas, Petrill, & Plomin 2010, "Generalist genes analysis of DNA markers associated with mathematical ability and disability reveals shared influence across ages and abilities"
^ Davis et al 2009 "Learning abilities and disabilities: generalist genes in early adolescence"
^ Calvin et al 2012, "Multivariate Genetic Analyses of Cognition and Academic Achievement from Two Population Samples of 174,000 and 166,000 School Children"
^ Chow et al 2013, "Generalist genes and cognitive abilities in Chinese twins"
^ Kovas & Plomin 2007, "Learning Abilities and Disabilities: Generalist Genes, Specialist Environments"
^ Light et al 1998, "Multivariate behavioral genetic analysis of achievement and cognitive measures in reading-disabled and control twin pair"
^ Knopik, Alarcon, & DeFries 1997, "Comorbidity of mathematics and reading deficits: Evidence for a genetic etiology"
^ Harlaar et al 2005, "Genetic influences on early word recognition abilities and disabilities: a study of 7-year-old twins"
^ DeFries et al 1991, "Colorado Reading Project: An update"
^ Baker 1986, "Estimating genetic correlations among phenotypes: An analysis of criminal convictions and psychiatric-hospital diagnoses in Danish adoptees"
^ Vonberg & Bigdeli 2016, "Genetic Correlation Between Schizophrenia and Epilepsy"
^ Purcell et al 2009, "Common polygenic variation contributes to risk of schizophrenia and bipolar disorder"
^ Ripke et al 2011, "Genome-wide association study identifies five new schizophrenia loci"
^ ^a ^b ^c ^d ^e Psychiatric Genomics Consortium 2013, "Genetic relationship between 5 psychiatric disorders estimated from genome-wide SNPs",
^ Lichtenstein et al 2009, "Common genetic determinants of schizophrenia and bipolar disorder in Swedish families: a population-based study"
^ Franke et al 2016, "Genetic influences on schizophrenia and subcortical brain volumes: large-scale proof of concept"
^ ^a ^b ^c ^d ^e "Partitioning heritability analysis reveals a shared genetic basis of brain anatomy and schizophrenia", Lee et al 2016
^ ^a ^b Byrne et al 2016, "Genetic Correlation Analysis Suggests Association between Increased Self-Reported Sleep Duration in Adults and Schizophrenia and Type 2 Diabetes", Sleep
^ ^a ^b Power et al 2015, "Polygenic risk scores for schizophrenia and bipolar disorder predict creativity"
^ Wang et al 2016, "Genetic factor common to schizophrenia and HIV infection is associated with risky sexual behavior: antagonistic vs. synergistic pleiotropic SNPs enriched for distinctly different biological functions"
^ Lane et al 2016, "Genome-wide association analyses of sleep disturbance traits identify new loci and highlight shared genetics with neuropsychiatric and metabolic traits"
^ Dima et al 2016, "The polygenic risk for bipolar disorder influences brain regional function relating to visual and default state processing of emotional information"
^ Rommelse et al 2010, "Shared heritability of attention-deficit/hyperactivity disorder and autism spectrum disorder"
^ ^a ^b ^c Pinto et al 2016, "Understanding the covariation of tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms: a population-based adult twin study"
^ ^a ^b Mathews & Grados 2011, "Familiality of Tourette syndrome, obsessive-compulsive disorder, and attention-deficit/hyperactivity disorder: heritability analysis in a large sib-pair sample"
^ van Hulzen et al 2016, "Genetic overlap between Attention-Deficit/Hyperactivity Disorder and Bipolar Disorder: Evidence from GWAS meta-analysis"
^ ^a ^b ^c Hyde et al 2016, "Identification of 15 genetic loci associated with risk of major depression in individuals of European descent"
^ Ligthart & Boomsma 2012, "Causes of comorbidity: Pleiotropy or causality? Shared genetic and environmental influences on migraine and neuroticism"
^ ^a ^b ^c ^d ^e ^f Power & Pluess 2015, "Heritability estimates of the Big Five personality traits based on common genetic variants"
^ Eaves & Eysenck 1975, "The nature of extraversion: A genetical analysis"
^ ^a ^b ^c Gao et al 2016, "Genome-Wide Association Study of Loneliness Demonstrates a Role for Common Variation"
^ Lahey et al 2011, "Higher-order genetic and environmental structure of prevalent forms of child and adolescent psychopathology"
^ Spatola et al 2007, "A general population twin study of the CBCL/6-18 DSM-oriented scales"
^ Pettersson et al 2013, "Different neurodevelopmental symptoms have a common genetic etiology"
^ Tackett et al 2013, "Common genetic influences on negative emotionality and a general psychopathology factor in childhood and adolescence"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Mann et al 2017, "Sensation seeking and impulsive traits as personality endophenotypes for antisocial behavior: Evidence from two independent samples"
^ ^a ^b ^c O'Connor et al 1998a, "Genetic contributions to continuity, change, and co-occurrence of antisocial and depressive symptoms in adolescence"; O'Connor et al 1998b, "Co-occurrence of depressive symptoms and antisocial behaviour in adolescence: A common genetic liability"
^ McGuffin et al 2003, "The heritability of bipolar affective disorder and the genetic relationship to unipolar depression"
^ Cederlöf et al 2015, "Etiological overlap between obsessive-compulsive disorder and anorexia nervosa: a longitudinal cohort, multigenerational family and twin study"
^ Davis et al 2013, "Partitioning the heritability of Tourette syndrome and obsessive compulsive disorder reveals differences in genetic architecture"
^ Yu et al 2015, "Cross-disorder genome-wide analyses suggest a complex genetic relationship between Tourette's syndrome and OCD"
^ ^a ^b ^c Zilhao et al 2016, "Cross-Disorder Genetic Analysis of Tic Disorders, Obsessive-Compulsive, and Hoarding Symptoms"
^ Mathews et al 2014, "Partitioning the etiology of hoarding and obsessive-compulsive symptoms"
^ Iervolino et al 2011, "A multivariate twin study of obsessive-compulsive symptom dimensions"
^ Iervolino et al 2009, "Prevalence and heritability of compulsive hoarding: a twin study"
^ Nordsletten et al 2013, "Overlap and specificity of genetic and environmental influences on excessive acquisition and difficulties discarding possessions: Implications for hoarding disorder"
^ Tambs et al 2009, "Structure of genetic and environmental risk factors for dimensional representations of DSM-IV anxiety disorders"
^ Chantarujikapong et al 2001, "A twin study of generalized anxiety disorder symptoms, panic disorder symptoms and post-traumatic stress disorder in men"
^ Hettema et al 2005, "The structure of genetic and environmental risk factors for anxiety disorders in men and women"
^ Bulik et al 2010, "Understanding the relation between anorexia nervosa and bulimia nervosa in a Swedish national twin sample"
^ Munn et al 2010, "Bivariate analysis of disordered eating characteristics in adolescence and young adulthood"
^ Bulik et al 2003, "Genetic and environmental contributions to obesity and binge eating"
^ Sullivan et al 1998, "Genetic epidemiology of binging and vomiting"
^ O'Connor et al 2016, "Genetic and environmental associations between body dissatisfaction, weight preoccupation, and binge eating: Evidence for a common factor with differential loadings across symptom type"
^ "Anorexia nervosa and major depression: shared genetic and environmental risk factors", Wade et al 2000
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t Duncan et al 2016, “Genome-Wide Association Study Reveals First Locus for Anorexia Nervosa and Metabolic Correlations”
^ "Bulimia nervosa and major depression: a study of common genetic and environmental factors", Walters et al 1992
^ ^a ^b ^c Guerreiro et al 2016, "Genome-wide analysis of genetic correlation in dementia with Lewy bodies, Parkinson's and Alzheimer's diseases"
^ Waldron et al 2008, "Childhood Sexual Abuse Moderates Genetic Influences on Age at First Consensual Sexual Intercourse in Women"
^ Shakoor et al 2016, "Association between stressful life events and psychotic experiences in adolescence: evidence for gene-environment correlations"
^ Silberg et al 1987, "Genetic and environmental factors in primary dysmenorrhea and its relationship to anxiety, depression, and neuroticism"
^ ^a ^b Weiss et al 2016, "Personality Polygenes, Positive Affect, and Life Satisfaction"
^ Kendler et al 1987, "Symptoms of anxiety and symptoms of depression: same genes, different environments?"
^ Kendler et al 1992, "Major depression and generalized anxiety disorder. Same genes, (partly) different environments?"
^ Kendler 1996/2004, "Major depression and generalised anxiety disorder same genes, (Partly) different environments - Revisited"
^ Kendler et al 2007, "The sources of co-morbidity between major depression and generalized anxiety disorder in a Swedish national twin sample"
^ Middeldorp et al 2005, "The co-morbidity of anxiety and depression in the perspective of genetic epidemiology. A review of twin and family studies"
^ ^a ^b ^c Mather et al 2016, "An Underlying Common Factor, Influenced by Genetics and Unique Environment, Explains the Covariation Between Major Depressive Disorder, Generalized Anxiety Disorder, and Burnout: A Swedish Twin Study"
^ ^a ^b Kendler et al 1995, "The structure of the genetic and environmental risk factors for six major psychiatric disorders in women: phobia, generalized anxiety disorder, panic disorder, bulimia, major depression and alcoholism"
^ Kendler et al 1993, "Major depression and phobias: the genetic and environmental sources of comorbidity"
^ Gorwood 2004, "Generalized anxiety disorder and major depressive disorder comorbidity: an example of genetic pleiotropy?"
^ Klein et al 2003, "Family study of co-morbidity between major depressive disorder and anxiety"
^ Klein & Riso 1993, "Psychiatric disorders: problems of boundaries and comorbidity". In Basic Issues in Psychopathology (ed. C. G. Costello), pp. 19–66. Guilford Press
^ Neale & Kendler 1995, "Models of comorbidity for multifactorial disorders"
^ Heath et al 1993, "Testing hypotheses about direction of causation using cross-sectional family data"
^ Duffy & Martin 1994, "Inferring the direction of causation in cross-sectional twin data: theoretical and empirical considerations"
^ Stringer et al 2016, "Genome-wide association study of lifetime cannabis use based on a large meta-analytic sample of 32330 subjects from the International Cannabis Consortium"
^ Treuer et al 2016, "Heritability of high sugar consumption through drinks and the genetic correlation with substance use"
^ Carey et al 2016, "Reward-related ventral striatum activity links polygenic risk for attention-deficit/hyperactivity disorder to problematic alcohol use in young adulthood"
^ ^a ^b Johnson et al 2011, "Does Education Confer a Culture of Healthy Behavior? Smoking and Drinking Patterns in Danish Twins"
^ Boomsma et al 1987b, "Factor and simplex models for repeated measures: Application to two psychomotor measures of alcohol sensitivity in twins"
^ Martin & Boomsma 1989, "Willingness to drive when drunk and personality: A twin study"
^ Sirota et al 2009, "Autoimmune disease classification by inverse association with SNP alleles"
^ Jostins et al 2012, "Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease"
^ Venema et al 2016, "The genetic background of Inflammatory Bowel Disease: From correlation to causality"
^ ^a ^b Lønnberg et al 2016, "Association of Psoriasis With the Risk for Type 2 Diabetes Mellitus and Obesity"
^ Do et al 2013, "Common variants associated with plasma triglycerides and risk for coronary artery disease"
^ ^a ^b ^c ^d ^e ^f LeBlanc et al 2016, "Identifying Novel Gene Variants in Coronary Artery Disease and Shared Genes with Several Cardiovascular Risk Factors"
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ van Iperen et al 2016, "Genetic analysis of emerging risk factors in coronary artery disease"
^ Zacho et al 2008, "Genetically elevated C-reactive protein and ischemic vascular disease"
^ Márquez et al 2016, "A combined large-scale meta-analysis identifies COG6 as a novel shared risk locus for rheumatoid arthritis and systemic lupus erythematosus"
^ Criswell et al 2005, "Analysis of families in the multiple autoimmune disease genetics consortium (MADGC) collection: the PTPN22 620W allele associates with multiple autoimmune phenotypes"
^ ^a ^b Chen et al 2014, "Estimation and partitioning of (co)heritability of inflammatory bowel disease from GWAS and immunochip data"
^ Cleynen et al 2016, "Inherited determinants of Crohn's disease and ulcerative colitis phenotypes: a genetic association study"
^ Ek et al 2013, "Germline genetic contributions to risk for esophageal adenocarcinoma, Barretts Esophagus, and gastroesophageal reflux"
^ van 't Hof et al 2016, "Shared Genetic Risk Factors of Intracranial, Abdominal, and Thoracic Aneurysms"
^ Candia et al 2013, "Additive Genetic Variation in Schizophrenia Risk Is Shared by Populations of African and European Descent"
^ ^a ^b ^c Brown et al 2016, "Transethnic genetic correlation estimates from summary statistics"
^ Mosley et al 2016, "Defining a Contemporary Ischemic Heart Disease Genetic Risk Profile using Historical Data"
^ Zeng et al 2016, "Shared genetics and couple-associated environment are major contributors to the risk of both clinical and self-declared depression"
^ MacGregor et al 2006, "Bias, precision and heritability of self-reported and clinically measured height in Australian twins"
^ Hopkins et al 2014, "Chimpanzee Intelligence Is Heritable"
^ Mulders et al 2016, "Estimating the purebred-crossbred genetic correlation for uniformity of eggshell color in laying hens"
^ Palomar et al 2016, "Heritability of Batrachochytrium dendrobatidis burden and its genetic correlation with development time in a population of Common toad (Bufo spinosus)"
^ Muñoz et al 2016, "Rising Out of the Ashes: Additive Genetic Variation for Crown and Collar Resistance to Hymenoscyphus fraxineus in Fraxinus excelsior"
^ Ritland & Ritland, "Inferences about quantitative inheritance based on natural population structure in the yellow monkeyflower, Mimulus guttatus"
^ van Kleunen & Ritland 2004, "Predicting evolution of floral traits associated with mating system in a natural plant population"
^ van Kleunen & Ritland 2005, "Estimating Heritabilities and Genetic Correlations with Marker-Based Methods: An Experimental Test in Mimulus guttatus"
^ Mousseau et al 1998, "A novel method for estimating heritability using molecular markers"
^ Gray et al 1995, "Breeding for Resistance to Infectious Disease in Small Ruminants"
^ Cheverud and Buikstra 1981b, "Quantitative Genetics of Skeletal Nonmetric Traits in the Rhesus Monkeys on Cayo Santiago. II. Phenotypic, Genetic, and Environmental Correlations between traits"
^ Smith et al 1962, "Genetic parameters of British Large White bacon pigs"
^ Leamy 1977, "Genetic and Environmental Correlations of Morphometric Traits in Random-bred House Mice"
^ Bailey 1956, "A comparison of genetic and environmental principal components of morphogenesis in mice"
^ Andrew et al 2005, "Marker-based quantitative genetics in the wild?: The heritability and genetic correlation of chemical defenses in Eucalyptus"
^ Buechel et al 2016, "Artificial selection on male genitalia length alters female brain size"
^ Chester & Weera 2016, "Genetic correlation between alcohol preference and conditioned fear: Exploring a functional relationship"
^ Yadav et al 2016, "Genetic variability and correlation studies for quantitative traits in kodo millet (Paspalum scrobiculatum L.)"
^ Collet et al 2016, "Rapid evolution of the intersexual genetic correlation for fitness in Drosophila melanogaster"

Falconer 1960, Introduction to Quantitative Genetics, Ch. 19 "Correlated Characters"
Meehl 1967, "Theory-testing in psychology and physics: A methodological paradox"
Meehl 1990, "Why summaries of research on psychological theories are often uninterpretable"
Cohen 1994, "The Earth is Round (p<.05)"
Plomin et al 2012, Behavioral Genetics ISBN 1-4292-4215-9
van Dongen et al 2012, "The continuing value of twin studies in the -omics era"
Deary 2012, "Looking for 'System Integrity' in Cognitive Epidemiology"
Plomin et al 2016, "Top 10 Replicated Findings From Behavioral Genetics"
So & Sham 2016, "Polygenic score analyses of schizophrenia and bipolar disorder with cardiometabolic traits"

External links

[1] Falconer 1960

[2] Neale & Maes 1996, Methodology for genetics studies of twins and families (6th ed.). Dordrecht, The Netherlands: Kluwer.

[Plomin123-3] 123 of Plomin 2012

[4] 194-195 of Jensen 1980, Bias in Mental Testing

[Martin1977-5] Martin & Eaves 1977, "The Genetical Analysis of Covariance Structure"

[Eaves1978-6] Eaves et al 1978, "Model-fitting approaches to the analysis of human behaviour"

[7] Loehlin & Vandenberg 1968, "Genetic and environmental components in the covariation of cognitive abilities: An additive model", in Progress in Human Behaviour Genetics, ed. S. G. Vandenberg, pp. 261278. Johns Hopkins, Baltimore.

[8] Purcell 2002, "Variance components models for gene-environment interaction in twin analysis"

[Kohler2011-9] Kohler et al 2011, "Social Science Methods for Twins Data: Integrating Causality, Endowments and Heritability"

[10] Wagner & Zhang 2011, "The pleiotropic structure of the genotype-phenotype map: The evolvability of complex organisms"

[Cheverud1988-11] Cheverud 1988, "A comparison of genetic and phenotypic correlations"

[Krapohl2015-12] Krapohl et al 2015, "Phenome-wide analysis of genome-wide polygenic scores"

[Hagenaars2016-13] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az ^ba ^bb ^bc ^bd ^be ^bf ^bg ^bh ^bi ^bj ^bk ^bl ^bm ^bn ^bo ^bp ^bq ^br ^bs ^bt ^bu ^bv ^bw ^bx ^by ^bz ^ca ^cb ^cc ^cd ^ce ^cf ^cg ^ch ^ci ^cj ^ck ^cl ^cm ^cn ^co ^cp ^cq ^cr ^cs Hagenaars et al 2016, "Shared genetic aetiology between cognitive functions and physical and mental health in UK Biobank (N=112 151) and 24 GWAS consortia"

[Hill2016-14] Hill et al 2016, "Molecular genetic contributions to social deprivation and household income in UK Biobank (n=112,151)"

[Zheng2016-15] "LD Hub: a centralized database and web interface to perform LD score regression that maximizes the potential of summary level GWAS data for SNP heritability and genetic correlation analysis", Zheng et al 2016

[16] Sivakumaran et al 2011, "Abundant pleiotropy in human complex diseases and traits"

[Solovieff2013-17] Solovieff et al 2013, "Pleiotropy in complex traits: challenges and strategies"

[Cotsapas2011-18] Cotsapas et al 2011, "Pervasive sharing of genetic effects in autoimmune disease"

[Chambers2011-19] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Chambers et al 2011, "Genome-wide association study identifies loci influencing concentrations of liver enzymes in plasma"

[20] Pickrell 2015, "Fulfilling the promise of Mendelian randomization"

[21] Smith 2015, "Mendelian randomization: a premature burial?"; "Understanding Mendelian Randomization"

[22] Burgess et al 2016, "Beyond Mendelian randomization: how to interpret evidence of shared genetic predictors"

[23] Hagenaars et al 2016b, "Cognitive ability and physical health: a Mendelian randomization study"

[24] Bowden et al 2015, "Mendelian randomization with invalid instruments: effect estimation and bias detection through Egger regression"

[25] Falconer cites the example of chicken size and egg laying: chickens grown large for genetic reasons lay later, fewer, and larger eggs, while chickens grown large for environmental reasons lay quicker and more but normal sized eggs (pg315 of Falconer 1960); Falconer in Table 19.1 on pg316 also provides examples of opposite-signed phenotypic & genetic correlations: fleece-weight/length-of-wool & fleece weight/body-weight in sheep, and body-weight/egg-timing & body-weight/egg-production in chicken. One consequence of the negative chicken correlations was that, despite moderate heritabilities and a positive phenotypic correlation, selection had begun to fail to yield any improvements (pg329) according to "Genetic slippage in response to selection for multiple objectives", Dickerson 1955.

[Kruuk-26] Kruuk, Loeske E. B.; Slate, Jon; Pemberton, Josephine M.; Brotherstone, Sue; Guinness, Fiona; Clutton-Brock, Tim (2002). "Antler Size in Red Deer: Heritability and Selection but No Evolution" (PDF). Evolution. 56 (8): 1683–95. doi:10.1111/j.0014-3820.2002.tb01480.x. PMID 12353761.

[Krapohl2016-27] Krapohl & Plomin 2016, "Genetic link between family socioeconomic status and children's educational achievement estimated from genome-wide SNPs"

[28] 397 of Plomin et al 2012

[29] Munafo et al 2016, "Collider Scope: How selection bias can induce spurious associations"

[30] Hewitt et al 1988, "Resolving the causes of developmental continuity or 'tracking.' I. Longitudinal twin studies during growth"

[Deary2012-31] Deary et al 2012, "Genetic contributions to stability and change in intelligence from childhood to old age"

[32] "The substantial comorbidity between specific cognitive disabilities is largely due to genetic factors, meaning that the same genes affect different learning disabilities although there are also disability-specific genes." pg184-185 of Plomin et al 2012

[Rietveld2013-33] Rietveld et al 2013, "GWAS of 126,559 individuals identifies genetic variants associated with educational attainment"

[Rietveld2014-34] Rietveld et al 2014, "Common genetic variants associated with cognitive performance identified using the proxy-phenotype method"

[Andreassen2013-35] Andreassen et al 2013, "Improved Detection of Common Variants Associated with Schizophrenia and Bipolar Disorder Using Pleiotropy-Informed Conditional False Discovery Rate"

[36] Hazel 1943, "The Genetic Basis for Constructing Selection Indexes"

[37] Rae 1951, "The Importance of Genetic Correlations in Selection"

[38] Hazel & Lush 1943, "The efficiency of three methods of selection"

[39] Lerner 1950, Population genetics and animal improvement: as illustrated by the inheritance of egg production

[40] Falconer 1960, pg324-329

[41] Conner 2012, "Quantitative genetic approaches to evolutionary constraint: how useful?"

[42] Beldade et al 2002, "Developmental constraints versus flexibility in morphological evolution"

[43] Allen et al 2008, "Differences in the selection response of serially repeated color pattern characters: standing variation, development, and evolution"

[Lee2012-44] Lee et al 2012, "Estimation of pleiotropy between complex diseases using single-nucleotide polymorphism-derived genomic relationships and restricted maximum likelihood"

[BulikSullivan2015-45] "LD Score regression distinguishes confounding from polygenicity in genome-wide association studies", Bulik-Sullivan et al 2015 (see also Shi et al 2016); LDSC

[Loh2015-46] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q Loh et al 2015, "Contrasting regional architectures of schizophrenia and other complex diseases using fast variance components analysis"

[Shi2016-47] Shi et al 2016, "Contrasting the genetic architecture of 30 complex traits from summary association data"

[48] Lynch 2000, "Estimating genetic correlations in natural populations"

[49] Golan et al 2014, "Measuring missing heritability: Inferring the contribution of common variants"

[50] Posthuma & Boomsma 2000, "A note on the statistical power in extended twin designs"

[DeFries1987-51] DeFries et al 1987, "Genetic Stability of Cognitive Development From Childhood to Adulthood"

[52] Wray et al 2012, "Impact of diagnostic misclassification on estimation of genetic correlations using genome-wide genotypes"

[53] 317-318 of Falconer 1960

[Schmitt2007b-54] Schmitt et al 2007b, "Review of twin and family studies on neuroanatomic phenotypes and typical neurodevelopment"

[55] Almasy et al 1997, "Bivariate quantitative trait linkage analysis: pleiotropy versus co-incident linkages"

[56] Heath et al 1989, "Testing structural equation models for twin data using LISREL"

[57] Lee et al 2016, "Facial averageness and genetic quality: testing heritability, genetic correlation with attractiveness, and the paternal age effect"

[Hagenaars2016b-58] Hagenaars et al 2016b, "Genetic Prediction of Male Pattern Baldness"

[Deary2016-59] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Deary et al 2016, "Genetic contributions to self-reported tiredness"

[Harris2015-60] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Harris et al 2015, "Molecular genetic contributions to self-rated health"

[Okbay2016a-61] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab Okbay et al 2016, "Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses"

[62] Karvinen et al 2015, "Physical activity in adulthood: genes and mortality"

[63] Hjelmborg et al 2008, "Genetic Influences on Growth Traits of BMI: A Longitudinal Study of Adult Twins"

[Jones2016-64] Jones et al 2016, "Genome‐Wide Association Analyses in 128,266 Individuals Identifies New Morningness and Sleep Duration Loci"

[Lane2016-65] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah Lane et al 2016, "Genome-wide association analysis identifies novel loci for chronotype in 100,420 individuals from the UK Biobank"

[Heath1990-66] Heath et al 1990, "Evidence for Genetic Influences on Sleep Disturbance and Sleep Pattern in Twins"

[67] Wade et 2010, "Body mass index and breast size in women: same or different genes?"

[68] Hwang et al 2016, "Sweet Taste Perception is Associated with Body Mass Index at the Phenotypic and Genotypic Level"

[Day2015-69] ^ ^a ^b ^c ^d ^e ^f ^g Day et al 2015, "Genetic determinants of puberty timing in men and women: shared genetic aetiology between sexes and with health-related outcomes"

[Day2016-70] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at Day et al 2016, "Physical and neurobehavioral determinants of reproductive onset and success"

[Mustelin2009-71] Mustelin et al 2009, "Physical activity reduces the influence of genetic effects on BMI and waist circumference: a study in young adult twins"

[72] Schnurr et al 2016, "Genetic Correlation between Body Fat Percentage and Cardiorespiratory Fitness Suggests Common Genetic Etiology

[Vattikuti2012-73] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t Vattikuti et al 2012, "Heritability and Genetic Correlations Explained by Common SNPs for Metabolic Syndrome Traits"

[Nederend2016-74] Nederend et al 2016, "Heritability of heart rate recovery and vagal rebound after exercise"

[75] Eppinga et al 2016, "Identification of genomic loci associated with resting heart rate and shared genetic predictors with all-cause mortality"

[deGeus2003-76] Geus et al 2003, "Genetic correlation of exercise with heart rate and respiratory sinus arrhythmia"

[Kupper2005-77] Kupper et al 2005, "A genetic analysis of ambulatory cardiorespiratory coupling"

[78] Snieder et al 1997, "Heritability of respiratory sinus arrhythmia: Dependency on task and respiration rate"

[Trzaskowski2013b-79] Trzaskowski et al 2013, "DNA Evidence for Strong Genome-Wide Pleiotropy of Cognitive and Learning Abilities"

[Horikoshi2016-80] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Horikoshi et al 2016, "Genome-wide associations for birth weight and correlations with adult disease"

[Barban2016-81] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Barban et al 2016, "Genome-wide analysis identifies 12 loci influencing human reproductive behavior" (supplement)

[Black1982-82] Black 1982, "Quantitative genetics of anthropometric variation in the Solomon Islands"

[Adams2016-83] ^ ^a ^b ^c ^d ^e ^f ^g "Novel genetic loci underlying human intracranial volume identified through genome-wide association", Adams et al 2016

[Hodgson2016-84] Hodgson et al 2016, "Shared Genetic Factors Influence Head Motion During MRI and Body Mass Index"

[Pennington2000-85] Pennington et al 2000, "A twin MRI study of size variations in human brain"

[86] Posthuma et al 2000, "Multivariate genetic analysis of brain structure in an extended twin design"

[87] Baaré et al 2001, "Quantitative genetic modeling of variation in human brain morphology"

[Posthuma2002-88] Posthuma et al 2002, "The association between brain volume and intelligence is of genetic origin"

[89] Thompson et al 2002, "Mapping genetic influences on human brain structure"

[90] Wright et al 2002, "Genetic contributions to regional variability in human brain structure: methods and preliminary results"

[Carmelli2002-91] Carmelli et al 2002, "Quantitative genetic modeling of regional brain volumes and cognitive performance in older male twins"

[Posthuma2003-92] Posthuma et al 2003, "Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed"

[93] Pfefferbaum et al 2004, "Morphological changes in aging brain structures are differentially affected by time-linked environmental influences despite strong genetic stability"

[Hulshoff2006-94] Hulshoff Pol et al 2006, "Genetic contributions to human brain morphology and intelligence"

[95] Peper et al 2007, "Genetic influences on human brain structure: a review of brain imaging studies in twins"

[96] Schmitt et al 2007a, "A multivariate analysis of neuroanatomic relationships in a genetically informative pediatric sample"

[97] Schmitt et al 2008, "Identification of genetically mediated cortical networks: a multivariate study of pediatric twins and siblings"

[98] Panizzon et al 2009, "Distinct Genetic Influences on Cortical Surface Area and Cortical Thickness"

[Chiang2009-99] Chiang et al 2009, "Genetics of brain fiber architecture and intellectual performance"

[100] Schmitt et al 2010, "A Twin Study of Intracerebral Volumetric Relationships"

[Betjemann2010-101] Betjemann et al 2010, "Genetic Covariation Between Brain Volumes and IQ, Reading Performance, and Processing Speed"

[102] Rimol et al, 2010, "Cortical thickness is influenced by regionally specific genetic factors"

[103] Eyler et al, 2011, "Genetic patterns of correlation among subcortical volumes in humans: results from a magnetic resonance imaging twin study"

[104] Chen et al 2011, "Genetic Influences on Cortical Regionalization in the Human Brain"

[105] Chen et al 2012, "Hierarchical Genetic Organization of Human Cortical Surface Area"

[106] Chen et al 2013, "Genetic topography of brain morphology"

[107] Eyler et al 2014, "Conceptual and Data-based Investigation of Genetic Influences and Brain Asymmetry: A Twin Study of Multiple Structural Phenotypes"

[108] Rentería et al 2014, "Genetic architecture of subcortical brain regions: common and region-specific genetic contributions"

[109] Hibar et al 2015, "Common genetic variants influence human subcortical brain structures"

[110] Wen et al 2016, "Distinct Genetic Influences on Cortical and Subcortical Brain Structures"

[Shen2016-111] Shen et al 2016, "Heritability and genetic correlation between the cerebral cortex and associated white matter connections"

[Levine2015-112] Levine et al 2015, "Epigenetic age of the pre-frontal cortex is associated with neuritic plaques, amyloid load, and Alzheimer's disease related cognitive functioning"

[113] Turner et al 2005, "Genomic Susceptibility Loci for Brain Atrophy in Hypertensive Sibships From the GENOA Study"

[114] Kochunov et al 2009, "Analysis of genetic variability and whole genome linkage of whole-brain, subcortical and ependymal hyperintense white matter volume"

[115] Kochunov et al 2010, "Whole brain and regional hyperintense white matter volume and blood pressure: overlap of genetic loci produced by bivariate, whole-genome linkage analyses"

[116] Kochunov et al 2011, "Blood pressure and cerebral white matter share common genetic factors in Mexican Americans"

[117] Fennema-Notestine et al 2016, "White matter disease in midlife is heritable, related to hypertension, and shares some genetic influence with systolic blood pressure"

[Warrier2016b-118] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ "Genome-wide meta-analysis of cognitive empathy: heritability, and correlates with sex, neuropsychiatric conditions and brain anatomy", Warrier et al 2016

[119] Zhou et al 2016, "Genetic overlap between in-scanner head motion and the default network connectivity"

[120] Plomin, R., DeFries, J. C, & McClearn, G. E. (1980). Behavioral genetics: A primer. San Francisco: Freeman.

[121] Plomin & DeFries 1981 "Multivariate behavioral genetics and development: Twin studies". In L. Gedda, P. Parisi, & W. E. Nance (Eds.), Progress in clinical and biological research, Vol. 69B, Twin research 3: Intelligence, personality, and development (pp. 25-33). New York: Liss.

[122] Plomin, R., & DeFries, J. C. (1985). Origins of individual differences in infancy: The Colorado Adoption Project. Orlando, FL: Academic Press

[123] Bishop et al 2003, "Development genetic analysis of general cognitive ability from 1 to 12 years in a sample of adoptees, biological siblings, and twins"

[Trzaskowski2013a-124] Trzaskowski et al 2013, "DNA evidence for strong genetic stability and increasing heritability of intelligence from age 7 to 12"

[Neumann2016-125] "Single Nucleotide Polymorphism Heritability of a General Psychopathology Factor in Children", Neumann et al 2016

[126] Brooks et al 1990, "Reading performance and general cognitive ability: A multivariate genetic analysis of twin data"

[127] Cardon et al 1990, "Genetic correlations between reading performance and IQ in the Colorado Adoption Project"

[128] Arden et al 2015, "The association between intelligence and lifespan is mostly genetic"

[Tucker-Drob2016-129] Tucker-Drob et al 2016 , "Genetically-Mediated Associations Between Measures of Childhood Character and Academic Achievement"

[Luciano2006-130] Luciano et al 2006, "The heritability of conscientiousness facets and their relationship to IQ and academic achievement"

[Marioni2014-131] Marioni et al 2014, "Molecular genetic contributions to socioeconomic status and intelligence"

[Wood2010-132] ^ ^a ^b ^c ^d ^e ^f ^g Wood et al 2010, "Separation of genetic influences on attention deficit hyperactivity disorder symptoms and reaction time performance from those on IQ"

[Stergiakouli2016-133] "Association between polygenic risk scores for attention-deficit hyperactivity disorder and educational and cognitive outcomes in the general population", Stergiakouli et al 2016

[Robinson2016-134] Robinson et al 2016, "Genetic risk for autism spectrum disorders and neuropsychiatric variation in the general population"

[Petrill1993-135] Petrill & Thompson 1993, "The phenotypic and genetic relationships among measures of cognitive ability, temperament, and scholastic achievement"

[136] Thompson et al 1988, "Multivariate analysis of cognitive and temperament measures in 24-month-old adoptive and nonadoptive sibling pairs"

[137] Husén 1959, Psychological Twin Research

[138] Sundet et al 2005, "Resolving the genetic and environmental sources of the correlation between height and intelligence: a study of nearly 2600 Norwegian male twin pairs"

[139] Silventoinen et al 2006, "Genetic contributions to the association between height and intelligence: Evidence from Dutch twin data from childhood to middle age"

[140] Beauchamp et al 2011, "On the sources of the height-intelligence correlation: new insights from a bivariate ACE model with assortative mating"

[141] Keller et al 2013, "The genetic correlation between height and IQ: shared genes or assortative mating?"

[142] Kuntsi & Stevenson 2001, "Psychological mechanisms in hyperactivity: II. The role of genetic factors"

[143] Nigg et al 2004, "Evaluating the endophenotype model of ADHD neuropsychological deficit: results for parents and siblings of children with ADHD combined and inattentive subtypes"

[144] Bidwell et al 2007, "Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder"

[145] Luciano et al 2004a, "A genetic investigation of the covariation among inspection time, choice reaction time, and IQ subtest scores"

[Miller2012-146] Miller et al 2012, "The heritability and genetic correlates of mobile phone use: a twin study of consumer behavior"

[Johnson2006-147] Johnson et al 2006, "Genetic and environmental influences on academic achievement trajectories during adolescence"

[148] Baker et al 2006, "Genetics of Educational Attainment in Australian Twins: Sex Differences and Secular Changes"

[Belsky2016-149] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Belsky et al 2016, "The genetics of success: How single-nucleotide polymorphisms associated with educational attainment relate to life-course development"

[Tambs1989-150] Tambs et al 1989, "Genetic and environmental contributions to the covariance between occupational status, educational attainment, and IQ: A study of twins"

[Lichtenstein1997-151] Lichtenstein & Pedersen 1997, "Does genetic variance for cognitive abilities account for genetic variance in educational achievement and occupational status? A study of twins reared apart and twins reared together"

[152] Behrman et al 1977, "Controlling for and measuring the effects of genetic and family environment in equations for schooling and labour market success", In Kinometrics, ed. P. Taubman. North Holland: Amsterdam

[153] Johnson et al 2010, "Education reduces the effects of genetic susceptibilities to poor physical health"

[Boardman2015-154] Boardman et al 2015, "What can genes tell us about the relationship between education and health?"

[155] Greven et al 2009, "More than just IQ: school achievement is predicted by self-perceived abilities - but for genetic rather than environmental reasons"

[Krapohl2014-156] ^ ^a ^b ^c ^d ^e ^f ^g ^h Krapohl et al 2014, "The high heritability of educational achievement reflects many genetically influenced traits, not just intelligence"

[157] Hicks et al 2008, "Moderating effects of personality on the genetic and environmental influences of school grades helps to explain sex differences in scholastic achievement"

[Rimfeld2016b-158] Rimfeld et al 2016, "True grit and genetics: Predicting academic achievement from personality"

[Mottus2016-159] ^ ^a ^b ^c ^d ^e ^f ^g "Educational attainment and personality are genetically intertwined", Mottus et al 2016

[160] Gottschling et al 2012, "The prediction of school achievement from a behavior genetic perspective: Results from the German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS)"

[161] Spinath et al 2008, "The nature and nurture of intelligence and motivation in the origins of sex differences in elementary school achievement"

[Okbay2016b-162] ^ ^a ^b ^c ^d ^e ^f ^g Okbay et al 2016, "Genome-wide association study identifies 74 loci associated with educational attainment"

[Hicks2008-163] Hicks et al 2008, "Moderating effects of personality on the genetic and environmental influences of school grades helps to explain sex differences in scholastic achievement"

[Johnson2005-164] Johnson et al 2005, "Disruptive behavior and school grades: Genetic and environmental relations in 11-year-olds"

[165] Newsome et al 2014, "Genetic and environmental influences on the co-occurrence of early academic achievement and externalizing behavior"

[166] Polderman et al 2010, "A systematic review of prospective studies on attention problems and academic achievement"

[167] Saudino & Plomin 2007, "Why are hyperactivity and academic achievement related?"

[168] Harlaar et al 2011, "Associations between reading achievement and independent reading in early elementary school: A genetically-informative cross-lagged study"

[169] Harlaar et al 2007, "Reading exposure: a (largely) environmental risk factor with environmentally-mediated effects on reading performance in the primary school years"

[170] Little et al 2016, "Exploring the Co-Development of Reading Fluency and Reading Comprehension: A Twin Study"

[171] Weiner et al 2016, "Polygenic transmission disequilibrium confirms that common and rare variation act additively to create risk for autism spectrum disorders"

[172] Vermeiren et al 2012, "Do genetic factors contribute to the relation between education and metabolic risk factors in young adults? A twin study"

[173] Zadro et al 2016, "Does educational attainment increase the risk of low back pain when genetics is considered? A population based study of Spanish twins"

[174] Silventoinen et al 2004, "Heritability of body height and educational attainment in an international context: comparison of adult twins in Minnesota and Finland"

[175] Marioni et al 2016, "Genetic variants linked to education predict longevity"

[176] Gill et al 1985, "Further evidence for genetic influences on educational achievement"

[Kovas2007-177] Kovas et al 2007, "The genetic and environmental origins of learning abilities and disabilities in the early school years"

[Markowitz2005-178] Markowitz et al 2005, "The etiology of mathematical and reading (dis)ability covariation in a sample of Dutch twins"

[179] Davis et al 2014, "The correlation between reading and mathematics ability at age twelve has a substantial genetic component"

[Rimfeld2015-180] Rimfeld et al 2015, "Pleiotropy across academic subjects at the end of compulsory education"

[Rimfeld2016a-181] Rimfeld et al 2016, "Genetics affects choice of academic subjects as well as achievement"

[182] Martin 1975, "The inheritance of scholastic abilities in a sample of twins. II. Genetical analysis of examination results"

[183] Bartels et al 2002, "Heritability of educational achievement in 12-year-olds and the overlap with cognitive ability"

[184] Calvin et al 2012, "Multivariate genetic analyses of cognition and academic achievement from two population samples of 174,000 and 166,000 school children"

[185] Johnson et al 2009, "Genetic and environmental transactions underlying educational attainment"

[186] Wainwright et al 2005a, "The genetic basis of academic achievement on the Queensland Core Skills Test and its shared genetic variance with IQ"; Wainwright et al 2005b, "Multivariate Genetic Analysis of Academic Skills of the Queensland Core Skills Test and IQ Highlight the Importance of Genetic g"

[187] Chambers 2000, "Academic achievement and IQ: A longitudinal genetic analysis" (as cited in Wainwright et al 2005)

[188] Petrill & Wilkerson 2000, "Intelligence and achievement: A behavioral genetic perspective"

[189] Thompson et al 1991, "Associations between cognitive abilities and scholastic achievement: Genetic overlap but environmental differences"

[190] Wadsworth et al 1995b, "Cognitive ability and academic achievement in the Colorado Adoption Project: A multivariate genetic analysis of parent-offspring and sibling data"

[Gillis1993-191] Gillis et al 1993, Comorbidity of Reading and Mathematics Disabilities: Genetic and Environmental Etiologies

[192] Wadsworth, S. J. (1994). "School achievement". In J. C. DeFries, R. Plomin, and D. W. Fulker (eds.), Nature and Nurture During Middle Childhood, Blackwell, Oxford

[193] Wadsworth et al 1995a, "Covariation among measures of cognitive ability and academic achievement in the Colorado Adoption Project: Sibling analysis"

[Bell2016-194] ^ ^a ^b ^c ^d ^e ^f ^g Bell et al 2016, "PgmNr 430: GWASs of ability to carry a musical tune and mathematical educational attainment"

[Warrier2016a-195] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Genome-wide analyses of empathy and systemizing: heritability and correlates with sex, education, and psychiatric risk", Warrier et al 2016

[196] Hanscombe et al 2011, "Chaotic homes and school achievement: A twin study"

[197] Haworth et al 2013, "Understanding the science-learning environment: A genetically sensitive approach"

[198] Smith et al 2016, "Food fussiness and food neophobia share a common etiology in early childhood"

[199] Randall et al 2016, "Toward a genetic understanding of dental fear: evidence of heritability"

[Olson1989-200] Olson et al 1989, "Specific deficits in component reading and language skills: Genetic and environmental influences", Journal of Learning Disabilities

[201] Tuvblad et al 2016, "Heritability and Longitudinal Stability of Planning and Behavioral Disinhibition Based on the Porteus Maze Test"

[202] Haworth et al 2009, "Generalist Genes and High Cognitive Abilities"

[203] Andrews et al 2009, "Neurodevelopmental disorders: Cluster 2 of the proposed meta-structure for DSM-V and ICD-11"

[204] Docherty, Kovas, Petrill, & Plomin 2010, "Generalist genes analysis of DNA markers associated with mathematical ability and disability reveals shared influence across ages and abilities"

[205] Davis et al 2009 "Learning abilities and disabilities: generalist genes in early adolescence"

[206] Calvin et al 2012, "Multivariate Genetic Analyses of Cognition and Academic Achievement from Two Population Samples of 174,000 and 166,000 School Children"

[207] Chow et al 2013, "Generalist genes and cognitive abilities in Chinese twins"

[208] Kovas & Plomin 2007, "Learning Abilities and Disabilities: Generalist Genes, Specialist Environments"

[209] Light et al 1998, "Multivariate behavioral genetic analysis of achievement and cognitive measures in reading-disabled and control twin pair"

[210] Knopik, Alarcon, & DeFries 1997, "Comorbidity of mathematics and reading deficits: Evidence for a genetic etiology"

[211] Harlaar et al 2005, "Genetic influences on early word recognition abilities and disabilities: a study of 7-year-old twins"

[212] DeFries et al 1991, "Colorado Reading Project: An update"

[213] Baker 1986, "Estimating genetic correlations among phenotypes: An analysis of criminal convictions and psychiatric-hospital diagnoses in Danish adoptees"

[214] Vonberg & Bigdeli 2016, "Genetic Correlation Between Schizophrenia and Epilepsy"

[215] Purcell et al 2009, "Common polygenic variation contributes to risk of schizophrenia and bipolar disorder"

[216] Ripke et al 2011, "Genome-wide association study identifies five new schizophrenia loci"

[PGC2013-217] Psychiatric Genomics Consortium 2013, "Genetic relationship between 5 psychiatric disorders estimated from genome-wide SNPs",

[218] Lichtenstein et al 2009, "Common genetic determinants of schizophrenia and bipolar disorder in Swedish families: a population-based study"

[219] Franke et al 2016, "Genetic influences on schizophrenia and subcortical brain volumes: large-scale proof of concept"

[Lee2016-220] "Partitioning heritability analysis reveals a shared genetic basis of brain anatomy and schizophrenia", Lee et al 2016

[Byrne2016-221] Byrne et al 2016, "Genetic Correlation Analysis Suggests Association between Increased Self-Reported Sleep Duration in Adults and Schizophrenia and Type 2 Diabetes", Sleep

[Power2015a-222] Power et al 2015, "Polygenic risk scores for schizophrenia and bipolar disorder predict creativity"

[223] Wang et al 2016, "Genetic factor common to schizophrenia and HIV infection is associated with risky sexual behavior: antagonistic vs. synergistic pleiotropic SNPs enriched for distinctly different biological functions"

[Lane2016b-224] Lane et al 2016, "Genome-wide association analyses of sleep disturbance traits identify new loci and highlight shared genetics with neuropsychiatric and metabolic traits"

[225] Dima et al 2016, "The polygenic risk for bipolar disorder influences brain regional function relating to visual and default state processing of emotional information"

[226] Rommelse et al 2010, "Shared heritability of attention-deficit/hyperactivity disorder and autism spectrum disorder"

[Pinto2016-227] Pinto et al 2016, "Understanding the covariation of tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms: a population-based adult twin study"

[Mathews2011-228] Mathews & Grados 2011, "Familiality of Tourette syndrome, obsessive-compulsive disorder, and attention-deficit/hyperactivity disorder: heritability analysis in a large sib-pair sample"

[229] van Hulzen et al 2016, "Genetic overlap between Attention-Deficit/Hyperactivity Disorder and Bipolar Disorder: Evidence from GWAS meta-analysis"

[Hyde2016-230] Hyde et al 2016, "Identification of 15 genetic loci associated with risk of major depression in individuals of European descent"

[231] Ligthart & Boomsma 2012, "Causes of comorbidity: Pleiotropy or causality? Shared genetic and environmental influences on migraine and neuroticism"

[Power2015b-232] ^ ^a ^b ^c ^d ^e ^f Power & Pluess 2015, "Heritability estimates of the Big Five personality traits based on common genetic variants"

[233] Eaves & Eysenck 1975, "The nature of extraversion: A genetical analysis"

[Gao2016-234] Gao et al 2016, "Genome-Wide Association Study of Loneliness Demonstrates a Role for Common Variation"

[235] Lahey et al 2011, "Higher-order genetic and environmental structure of prevalent forms of child and adolescent psychopathology"

[236] Spatola et al 2007, "A general population twin study of the CBCL/6-18 DSM-oriented scales"

[237] Pettersson et al 2013, "Different neurodevelopmental symptoms have a common genetic etiology"

[238] Tackett et al 2013, "Common genetic influences on negative emotionality and a general psychopathology factor in childhood and adolescence"

[Mann2017-239] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Mann et al 2017, "Sensation seeking and impulsive traits as personality endophenotypes for antisocial behavior: Evidence from two independent samples"

[OConnor1998-240] O'Connor et al 1998a, "Genetic contributions to continuity, change, and co-occurrence of antisocial and depressive symptoms in adolescence"; O'Connor et al 1998b, "Co-occurrence of depressive symptoms and antisocial behaviour in adolescence: A common genetic liability"

[241] McGuffin et al 2003, "The heritability of bipolar affective disorder and the genetic relationship to unipolar depression"

[242] Cederlöf et al 2015, "Etiological overlap between obsessive-compulsive disorder and anorexia nervosa: a longitudinal cohort, multigenerational family and twin study"

[243] Davis et al 2013, "Partitioning the heritability of Tourette syndrome and obsessive compulsive disorder reveals differences in genetic architecture"

[244] Yu et al 2015, "Cross-disorder genome-wide analyses suggest a complex genetic relationship between Tourette's syndrome and OCD"

[Zilhao2016-245] Zilhao et al 2016, "Cross-Disorder Genetic Analysis of Tic Disorders, Obsessive-Compulsive, and Hoarding Symptoms"

[246] Mathews et al 2014, "Partitioning the etiology of hoarding and obsessive-compulsive symptoms"

[247] Iervolino et al 2011, "A multivariate twin study of obsessive-compulsive symptom dimensions"

[248] Iervolino et al 2009, "Prevalence and heritability of compulsive hoarding: a twin study"

[249] Nordsletten et al 2013, "Overlap and specificity of genetic and environmental influences on excessive acquisition and difficulties discarding possessions: Implications for hoarding disorder"

[250] Tambs et al 2009, "Structure of genetic and environmental risk factors for dimensional representations of DSM-IV anxiety disorders"

[251] Chantarujikapong et al 2001, "A twin study of generalized anxiety disorder symptoms, panic disorder symptoms and post-traumatic stress disorder in men"

[252] Hettema et al 2005, "The structure of genetic and environmental risk factors for anxiety disorders in men and women"

[253] Bulik et al 2010, "Understanding the relation between anorexia nervosa and bulimia nervosa in a Swedish national twin sample"

[254] Munn et al 2010, "Bivariate analysis of disordered eating characteristics in adolescence and young adulthood"

[255] Bulik et al 2003, "Genetic and environmental contributions to obesity and binge eating"

[256] Sullivan et al 1998, "Genetic epidemiology of binging and vomiting"

[257] O'Connor et al 2016, "Genetic and environmental associations between body dissatisfaction, weight preoccupation, and binge eating: Evidence for a common factor with differential loadings across symptom type"

[258] "Anorexia nervosa and major depression: shared genetic and environmental risk factors", Wade et al 2000

[Duncan2016-259] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t Duncan et al 2016, “Genome-Wide Association Study Reveals First Locus for Anorexia Nervosa and Metabolic Correlations”

[260] "Bulimia nervosa and major depression: a study of common genetic and environmental factors", Walters et al 1992

[Guerreiro2016-261] Guerreiro et al 2016, "Genome-wide analysis of genetic correlation in dementia with Lewy bodies, Parkinson's and Alzheimer's diseases"

[262] Waldron et al 2008, "Childhood Sexual Abuse Moderates Genetic Influences on Age at First Consensual Sexual Intercourse in Women"

[263] Shakoor et al 2016, "Association between stressful life events and psychotic experiences in adolescence: evidence for gene-environment correlations"

[264] Silberg et al 1987, "Genetic and environmental factors in primary dysmenorrhea and its relationship to anxiety, depression, and neuroticism"

[Weiss2016-265] Weiss et al 2016, "Personality Polygenes, Positive Affect, and Life Satisfaction"

[266] Kendler et al 1987, "Symptoms of anxiety and symptoms of depression: same genes, different environments?"

[267] Kendler et al 1992, "Major depression and generalized anxiety disorder. Same genes, (partly) different environments?"

[268] Kendler 1996/2004, "Major depression and generalised anxiety disorder same genes, (Partly) different environments - Revisited"

[269] Kendler et al 2007, "The sources of co-morbidity between major depression and generalized anxiety disorder in a Swedish national twin sample"

[270] Middeldorp et al 2005, "The co-morbidity of anxiety and depression in the perspective of genetic epidemiology. A review of twin and family studies"

[Mather2016-271] Mather et al 2016, "An Underlying Common Factor, Influenced by Genetics and Unique Environment, Explains the Covariation Between Major Depressive Disorder, Generalized Anxiety Disorder, and Burnout: A Swedish Twin Study"

[Kendler1995-272] Kendler et al 1995, "The structure of the genetic and environmental risk factors for six major psychiatric disorders in women: phobia, generalized anxiety disorder, panic disorder, bulimia, major depression and alcoholism"

[273] Kendler et al 1993, "Major depression and phobias: the genetic and environmental sources of comorbidity"

[274] Gorwood 2004, "Generalized anxiety disorder and major depressive disorder comorbidity: an example of genetic pleiotropy?"

[275] Klein et al 2003, "Family study of co-morbidity between major depressive disorder and anxiety"

[276] Klein & Riso 1993, "Psychiatric disorders: problems of boundaries and comorbidity". In Basic Issues in Psychopathology (ed. C. G. Costello), pp. 19–66. Guilford Press

[277] Neale & Kendler 1995, "Models of comorbidity for multifactorial disorders"

[278] Heath et al 1993, "Testing hypotheses about direction of causation using cross-sectional family data"

[279] Duffy & Martin 1994, "Inferring the direction of causation in cross-sectional twin data: theoretical and empirical considerations"

[280] Stringer et al 2016, "Genome-wide association study of lifetime cannabis use based on a large meta-analytic sample of 32330 subjects from the International Cannabis Consortium"

[281] Treuer et al 2016, "Heritability of high sugar consumption through drinks and the genetic correlation with substance use"

[282] Carey et al 2016, "Reward-related ventral striatum activity links polygenic risk for attention-deficit/hyperactivity disorder to problematic alcohol use in young adulthood"

[Johnson2011-283] Johnson et al 2011, "Does Education Confer a Culture of Healthy Behavior? Smoking and Drinking Patterns in Danish Twins"

[284] Boomsma et al 1987b, "Factor and simplex models for repeated measures: Application to two psychomotor measures of alcohol sensitivity in twins"

[285] Martin & Boomsma 1989, "Willingness to drive when drunk and personality: A twin study"

[286] Sirota et al 2009, "Autoimmune disease classification by inverse association with SNP alleles"

[287] Jostins et al 2012, "Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease"

[288] Venema et al 2016, "The genetic background of Inflammatory Bowel Disease: From correlation to causality"

[Lønnberg2016-289] Lønnberg et al 2016, "Association of Psoriasis With the Risk for Type 2 Diabetes Mellitus and Obesity"

[290] Do et al 2013, "Common variants associated with plasma triglycerides and risk for coronary artery disease"

[LeBlanc2016-291] ^ ^a ^b ^c ^d ^e ^f LeBlanc et al 2016, "Identifying Novel Gene Variants in Coronary Artery Disease and Shared Genes with Several Cardiovascular Risk Factors"

[vanIperen2016-292] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ van Iperen et al 2016, "Genetic analysis of emerging risk factors in coronary artery disease"

[293] Zacho et al 2008, "Genetically elevated C-reactive protein and ischemic vascular disease"

[294] Márquez et al 2016, "A combined large-scale meta-analysis identifies COG6 as a novel shared risk locus for rheumatoid arthritis and systemic lupus erythematosus"

[295] Criswell et al 2005, "Analysis of families in the multiple autoimmune disease genetics consortium (MADGC) collection: the PTPN22 620W allele associates with multiple autoimmune phenotypes"

[Chen2014-296] Chen et al 2014, "Estimation and partitioning of (co)heritability of inflammatory bowel disease from GWAS and immunochip data"

[297] Cleynen et al 2016, "Inherited determinants of Crohn's disease and ulcerative colitis phenotypes: a genetic association study"

[Ek2013-298] Ek et al 2013, "Germline genetic contributions to risk for esophageal adenocarcinoma, Barretts Esophagus, and gastroesophageal reflux"

[Hof2016-299] van 't Hof et al 2016, "Shared Genetic Risk Factors of Intracranial, Abdominal, and Thoracic Aneurysms"

[300] Candia et al 2013, "Additive Genetic Variation in Schizophrenia Risk Is Shared by Populations of African and European Descent"

[Brown2016-301] Brown et al 2016, "Transethnic genetic correlation estimates from summary statistics"

[302] Mosley et al 2016, "Defining a Contemporary Ischemic Heart Disease Genetic Risk Profile using Historical Data"

[303] Zeng et al 2016, "Shared genetics and couple-associated environment are major contributors to the risk of both clinical and self-declared depression"

[304] MacGregor et al 2006, "Bias, precision and heritability of self-reported and clinically measured height in Australian twins"

[305] Hopkins et al 2014, "Chimpanzee Intelligence Is Heritable"

[306] Mulders et al 2016, "Estimating the purebred-crossbred genetic correlation for uniformity of eggshell color in laying hens"

[307] Palomar et al 2016, "Heritability of Batrachochytrium dendrobatidis burden and its genetic correlation with development time in a population of Common toad (Bufo spinosus)"

[308] Muñoz et al 2016, "Rising Out of the Ashes: Additive Genetic Variation for Crown and Collar Resistance to Hymenoscyphus fraxineus in Fraxinus excelsior"

[309] Ritland & Ritland, "Inferences about quantitative inheritance based on natural population structure in the yellow monkeyflower, Mimulus guttatus"

[310] van Kleunen & Ritland 2004, "Predicting evolution of floral traits associated with mating system in a natural plant population"

[311] van Kleunen & Ritland 2005, "Estimating Heritabilities and Genetic Correlations with Marker-Based Methods: An Experimental Test in Mimulus guttatus"

[312] Mousseau et al 1998, "A novel method for estimating heritability using molecular markers"

[313] Gray et al 1995, "Breeding for Resistance to Infectious Disease in Small Ruminants"

[314] Cheverud and Buikstra 1981b, "Quantitative Genetics of Skeletal Nonmetric Traits in the Rhesus Monkeys on Cayo Santiago. II. Phenotypic, Genetic, and Environmental Correlations between traits"

[315] Smith et al 1962, "Genetic parameters of British Large White bacon pigs"

[316] Leamy 1977, "Genetic and Environmental Correlations of Morphometric Traits in Random-bred House Mice"

[317] Bailey 1956, "A comparison of genetic and environmental principal components of morphogenesis in mice"

[318] Andrew et al 2005, "Marker-based quantitative genetics in the wild?: The heritability and genetic correlation of chemical defenses in Eucalyptus"

[319] Buechel et al 2016, "Artificial selection on male genitalia length alters female brain size"

[320] Chester & Weera 2016, "Genetic correlation between alcohol preference and conditioned fear: Exploring a functional relationship"

[321] Yadav et al 2016, "Genetic variability and correlation studies for quantitative traits in kodo millet (Paspalum scrobiculatum L.)"

[322] Collet et al 2016, "Rapid evolution of the intersexual genetic correlation for fitness in Drosophila melanogaster"

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]