Behavioural genetics, also commonly referred to as behaviour genetics, is the field of study that examines the role of genetic and environmental influences on animal (including human) behaviour. Often associated with the "nature versus nurture" debate, behavioural genetics is highly interdisciplinary, involving contributions from biology, neuroscience, genetics, epigenetics, ethology, psychology, and statistics. Behavioural geneticists study the inheritance of behavioural traits. In humans, this information is often gathered through the use of the twin study or adoption study. In animal studies, breeding, transgenesis, and gene knockout techniques are common. Psychiatric genetics is a closely related field.
Sir Francis Galton, a nineteenth-century intellectual, is recognized as one of the first behavioural geneticists. Galton, a cousin of Charles Darwin, studied the heritability of human ability, focusing on mental characteristics as well as eminence among close relatives in the English upper-class. In 1869, Galton published his results in Hereditary Genius. In his work, Galton "introduced multivariate analysis and paved the way towards modern Bayesian statistics" that are used throughout the sciences—launching what has been dubbed the "Statistical Enlightenment". Galton is often credited as the pioneer of eugenics.
In 1951, Calvin S. Hall in his seminal book chapter on behavioural genetics introduced the term "psychogenetics", which enjoyed some limited popularity in the 1960s and 1970s. However, it eventually disappeared from usage in favour of "behaviour genetics".
Behaviour genetics, per se, gained recognition as a research discipline with the publication in 1960 of the textbook Behavior Genetics by J.L. Fuller and W.R. Thompson. Nowadays, it is widely accepted that most behaviours in animals and humans are under some degree of genetic influence.
Underscoring the role of evolution in behavioural genetics, Theodosius Dobzhansky was elected the first president of the Behavior Genetics Association in 1972; the BGA bestows the Dobzhansky Award on researchers for their outstanding contributions to the field. In the early 1970s, Lee Ehrman, a doctoral student of Dobzhansky, wrote seminal papers describing the relationship between genotype frequency and mating success in Drosophila, lending impetus to the pursuit of genetic studies of behaviour in other animals. Studies on hygienic behaviour in honey bees were also carried out early in the history of the field. The social behaviour of honey bees has also been studied and recent work has focussed on the gene involved in the foraging behaviour of Drosophila; this essentially allowed for deriving a relationship between gene expression and behaviour, where the gene regulating foraging behaviour in Drosophila also regulated social behaviour in bees.
The primary goal of behavioural genetics is to establish causal relationships between genes and behaviour. Initial approaches to these questions often use behaviour genetic methods such as the twin study or adoption design (in humans). In animal research selection experiments have often been employed. For example, laboratory house mice have been bred for open-field behaviour, thermoregulatory nesting, and voluntary wheel-running behaviour.  A range of methods in these designs are covered on those pages.
If functional brain systems or neurotransmitter systems have been mapped to a behaviour, genes involved in theses systems can be examined for alleles linked to the behaviour. For instance an abnormal gene coding for glutamate could be a candidate gene for schizophrenia.
The Human Genome Project has allowed scientists to understand the coding sequence of human DNA nucleotides. This made readily possible many hundreds of research studies which are much less hypothesis-driven. In these association studies, researchers test the relationship of behaviour to polymorphisms across the genome, sometimes in hypothesis-driven pathway analyses. Pathways for most common traits are believed to be complex and involve many small genetic effects.. Initial attempts to associate particular genes (or at least chromosomal positions) to behaviour often involve a search for Quantitative trait loci (QTL).
Notable behavioural geneticists
Notable behavioural geneticists include Dorret Boomsma, Wim Crusio (the founding editor of the journal Genes, Brain and Behavior), John DeFries, Lindon Eaves, David Fulker, Irving Gottesman, John K. Hewitt, Jerry Hirsch, Kenneth Kendler, John C. Loehlin, Nick Martin, Gerald McClearn, Robert Plomin, Theodore Reich (a pioneer in psychiatric genetics), Hans van Abeelen, and Steven G. Vandenberg (the founding editor of the journal Behavior Genetics).
Behavioural geneticists are active in a variety of scientific disciplines including biology, medicine, pharmacology, psychiatry, and psychology; thus, behavioural-genetic research is published in a variety of scientific journals, including Nature and Science. Journals that specifically publish research in behavioural genetics include Behavior Genetics, Molecular Psychiatry, Psychiatric Genetics, Twin Research and Human Genetics, Genes, Brain and Behavior, and the Journal of Neurogenetics.
There exist several learned societies in the broader area of behavioural genetics:
- Behavior Genetics Association
- International Behavioural and Neural Genetics Society
- International Society for Psychiatric Genetics
- Twin study
- Molecular genetics
- Behavioral epigenetics
- Biocultural evolution
- Human behavior genetics
- Behavioral neurogenetics
- Hereditary Genius: An Inquiry into Its Laws and Consequences. London: MacMillan and Co. 1869.
- Stigler SM (July 2010). "Darwin, Galton and the Statistical Enlightenment". Journal of the Royal Statistical Society, Series A 173 (3): 469–482. doi:10.1111/j.1467-985X.2010.00643.x.
- Hall CS (1951). "The genetics of behavior". In Stevens SS. Handbook of Experimental Psychology. New York: John Wiley and Sons. pp. 304–329.
- Grigorenko EL; Ravich-Shcherbo I (1997). "Russian psychogenetics". In Grigorenko EL. Psychology of Russia: Past, Present, Future. Commack, NY: Nova Science. pp. 83–124.
- Broadhurst PL (July 1969). "Psychogenetics of emotionality in the rat". Annals of the New York Academy of Sciences 159 (3): 806–24. Bibcode:1969NYASA.159..806B. doi:10.1111/j.1749-6632.1969.tb12980.x. PMID 5260300.
- Fuller JL; Thompson WR (1960). Behavior Genetics. New York: John Wiley and Sons.
- Plomin, Robert (1989). "Behavioral Genetics". Journal of Nervous and Mental Disease 177 (10): 645. doi:10.1097/00005053-198910000-00020.
- Ehrman L (1966). "Mating success and genotype frequency in Drosophila". Animal Behaviour 14 (2): 332–9. doi:10.1016/S0003-3472(66)80093-3. PMID 5956600.
- Ehrman L (February 1970). "Simulation of the mating advantage in mating of rare Drosophila males". Science 167 (3919): 905–6. Bibcode:1970Sci...167..905E. doi:10.1126/science.167.3919.905. PMID 5410860.
- Ehrman L (February 1970). "The mating advantage of rare males in Drosophila". Proc. Natl. Acad. Sci. U.S.A. 65 (2): 345–8. Bibcode:1970PNAS...65..345E. doi:10.1073/pnas.65.2.345. PMC 282908. PMID 5263769.
- Rothenbuhler WC (May 1964). "Behavior genetics of nest cleaning in honey bees. IV. Responses of F1 and backcross generations to disease-killed brood". Am. Zool. 4 (2): 111–123. doi:10.1093/icb/4.2.111. PMID 14172721.
- Rothenbuhler WC (1958). "Genetics and breeding of the honey bee". Annual Review of Entomology 3: 161–180. doi:10.1146/annurev.en.03.010158.001113.
- Christians JK (June 2005). "Behavioural genetics". BioEssays 27 (6): 664–666. doi:10.1002/bies.20247. PMID 15892115.
- DeFries JC; Hegmann JP; Halcomb RA (1974). "Response to 20 generations of selection for open-field activity in mice". Behavior 11 (4): 481–485. doi:10.1016/s0091-6773(74)90800-1.
- Lynch CB (1980). "Response to divergent selection for nesting behavior in Mus musculus". Genetics 96 (3): 757–765. PMC 1214374. PMID 7196362.
- Swallow JG; Carter PA; Garland T, Jr. (1998). "Artificial selection for increased wheel-running behavior in house mice" (PDF). Behavior Genetics 28 (3): 227–237. doi:10.1023/A:1021479331779. PMID 9670598.
- Crusio, Wim E. (2015). "Key issues in contemporary behavioral genetics". Current Opinion in Behavioral Sciences 2: 89. doi:10.1016/j.cobeha.2014.10.002.
- Crusio, W. E.; Gerlai, R. T., eds. (1999). Handbook of Molecular-Genetic Techniques for Brain and Behavior Research. Techniques in the Behavioral and Neural Sciences 13. Elsevier. ISBN 978-0-444-50239-1.
- Crusio, Wim E.; Sluyter, Frans; Gerlai, Robert T.; Pietropaolo, Susanna, eds. (2013). Behavioral Genetics of the Mouse: Genetics of Behavioral Phenotypes. Cambridge Handbooks in Behavioral Genetics 1. Cambridge University Press. ISBN 978-1-107-03481-5.
- Flint, Jonathan; Greenspan, Ralph J.; Kendler, Kenneth S. (28 January 2010). How Genes Influence Behavior. Oxford University Press. ISBN 978-0-19-955990-9. Lay summary (20 November 2013).
- Johnson, Wendy; Turkheimer, E.; Gottesman, Irving; Bouchard, Thomas (2009). "Beyond Heritability: Twin Studies in Behavioral Research" (PDF). Current Directions in Psychological Science 18 (4): 217–220. doi:10.1111/j.1467-8721.2009.01639.x. PMC 2899491. PMID 20625474. Retrieved 21 November 2010.
- Johnson, Wendy; Penke, Lars; Spinath, Frank M. (2011). "Understanding Heritability: What it is and What it is Not" (PDF). European Journal of Personality 25 (4): 287–294. doi:10.1002/per.835. ISSN 0890-2070. Retrieved 15 December 2013.
- Maxson, Stephen C. (10 October 2012). "Chapter 1: Behavioral Genetics". In Weiner, Irving B.; Nelson, Randy J.; Mizumori, Sheri. Handbook of Psychology (PDF). Volume 3: Behavioral Neuroscience. John Wiley & Sons. ISBN 978-0-470-89059-2. Archived from the original on 2013. Retrieved 15 December 2013.
- Panofsky, Aaron (2014). Misbehaving Science. Controversy and the Development of Behavior Genetics. Chicago: University of Chicago Press. ISBN 978-0-226-05831-3.
- Plomin, Robert; DeFries, John C.; Knopik, Valerie S.; Jenae M. Neiderhiser (24 September 2012). Behavioral Genetics. Shaun Purcell (Appendix: Statistical Methods in Behaviorial Genetics). Worth Publishers. ISBN 978-1-4292-4215-8. Retrieved 4 September 2013. Lay summary (4 September 2013).
- Spinath, Frank M.; Johnson, Wendy (2011). "Chapter 10: Behavior Genetics". In Chamorro-Premuzic, Tomas; von Stumm, Sophie; Furnham, Adrian. The Wiley-Blackwell Handbook of Individual Differences. United Kingdom: Blackwell Publishing Ltd. doi:10.1002/9781444343120. ISBN 978-1-4443-3438-8. Lay summary (10 July 2013).
McGue, Matt (5 May 2014). "Introduction to Human Behavioral Genetics". Coursera. Retrieved 10 June 2014. Free Massively Open Online Course on human behaviour genetics