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The '''Genetic history of Sardinia''' consists of the study of the [[gene pool]] of the islanders with two main objectives. The first is purely scientific and cultural and is to reconstruct the [[natural history]] of the population. It consists in understanding the extent, timing and methods of the foundation together with the subsequent or concomitant demographic and evolutionary dynamics. The other is instead applicative and has the aim of understanding the genetic causes of some pathologies by exploiting some peculiarities of the Sardinian population, which make it ideal for studies involving the use of [[genetic isolate]]s.
#REDIRECT [[Sardinian_people#Genetics]] {{Redirect category shell|

{{R to section}}
The geographical position of Sardinia and the mountainousness of its territory have meant that particular anthropological and genetic characteristics have been created in the Sardinian population, due to phenomena such as isolation, [[endogamy]] and evolutionary processes such as [[genetic drift]], in similarly to other European populations such as the [[Basques]], [[Lapps]] and [[Icelanders]]
}}

The high genetic variability implies a significant number of founding lines. Archeology indicates that the actual size of the Sardinian population was significant compared to other contemporary geographical areas. Great demographic crises, such as those caused by [[plague]] epidemics, have not been able to affect the original structure of the population.

==Studies==
===Autosomal studies===
Recent comparisons between the Sardinians' genome and that of some individuals from the Neolithic and the early Chalcolithic, who lived in the [[Alps|Alpine]] ([[Oetzi]]), German, and Hungarian regions, showed considerable similarities between the two populations, while at the same time consistent differences between the prehistoric samples and the present inhabitants of the same geographical areas were noted.<ref name=Gamba>[http://www.nature.com/ncomms/2014/141021/ncomms6257/full/ncomms6257.html Genome flux and stasis in a five millennium transect of European prehistory]</ref> From this it can be deduced that, while [[central Europe|central]] and northern Europe have undergone significant demographic changes due to post-Neolithic migrations, presumably from the eastern periphery of Europe ([[Pontic–Caspian steppe]]), Southern Europe and Sardinia in particular were affected less; Sardinians appear to be the population that has best preserved the [[Neolithic]] legacy of Western Europe.<ref name="Keller at al 2011, Nature">[http://www.nature.com/ncomms/journal/v3/n2/full/ncomms1701.html Keller at al 2011, Nature]</ref><ref name="Mathieson et al 2015, Nature">[http://www.nature.com/nature/journal/v528/n7583/full/nature16152.html Mathieson et al 2015, Nature]</ref><ref name="supp. info p.16">[http://www.nature.com/nature/journal/v528/n7583/extref/nature16152-s1.pdf supp. info (p.16)]</ref><ref name="mbe.oxfordjournals.org">[https://web.archive.org/web/20151205094106/http://mbe.oxfordjournals.org/content/32/12/3132.full.pdf+html ''A Common Genetic Origin for Early Farmers from Mediterranean Cardial and Central European LBK Cultures'', Olalde et al 2015, Molecular Biology and Evolution]</ref><ref name="nature.com">[http://www.nature.com/ncomms/2014/141021/ncomms6257/full/ncomms6257.html Gamba et al 2014, ''Genome flux and stasis in a five millennium transect of European prehistory'', Nature]</ref><ref name="cell.com">[http://www.cell.com/current-biology/abstract/S0960-9822%2815%2901516-X Omrak et al 2016, ''Genomic Evidence Establishes Anatolia as the Source of the European Neolithic Gene Pool'', Current Biology, Volume 26, Issue 2, p270–275, 25 January 2016]</ref><ref name=Haak>[http://biorxiv.org/content/early/2015/02/10/013433 Haak et al 2015, ''Massive migration from the steppe was a source for Indo-European languages in Europe'']</ref><ref name="supp. info p.120">[http://www.nature.com/nature/journal/v522/n7555/extref/nature14317-s1.pdf supp. info (p.120)]</ref><ref name="Gamba"/><ref>[https://web.archive.org/web/20160407092418/https://genographic.nationalgeographic.com/reference-populations-next-gen/ ''Reference Populations Genographic Project''. National Geographic]</ref>

A 2020 study by Fernandes et al. estimated that the current Sardinian genome derives roughly 62.5% from [[Neolithic]] [[Early European Farmers]] (EEF), 9.7% from the [[Mesolithic]] [[Western Hunter-Gatherer]]s (WHG), 13.9% from ancestry related to Neolithic Iranians of [[Ganj Dareh]] (or also [[Caucasus Hunter-Gatherer|Caucasus]]-related ancestry), 10.6% from the [[Bronze Age]] [[Western Steppe Herders]] (WSH) of the [[Yamnaya culture]] and, lastly, 3.4% from Late Neolithic Moroccans (partly of European origin).<ref name= Fernandes>{{cite journal |last1=Fernandes |first1=Daniel M. |title=The Spread of Steppe and Iranian Related Ancestry in the Islands of the Western Mediterranean |journal=Nature Ecology & Evolution |date= 24 February 2020|volume=4 |issue=3 |pages=334–345 |doi= 10.1038/s41559-020-1102-0|pmid=32094539 |pmc=7080320 |bibcode=2020NatEE...4..334F |s2cid= }}</ref><ref>[https://static-content.springer.com/esm/art%3A10.1038%2Fs41559-020-1102-0/MediaObjects/41559_2020_1102_MOESM1_ESM.pdf Supplementary information p.29]</ref>
Fernandes concluded that: "Major immigration into Sardinia began in the [[first millennium BC]] and, at present, no more than 56–62% of Sardinian ancestry is from its first farmers. This value is lower than previous estimates, highlighting that Sardinia, similar to every other region in Europe, has been a stage for major movement and mixtures of people".<ref name= Fernandes />
[[File:Supplementary Figure 17.png|360px|thumb|Three-way admixture model of present-day Sardinians by pre-2016 province]]
Another study from 2020 also found that the present-day Sardinian genome was shaped by immigration from the [[Iron Age]] onwards, which can be modelled well using three source populations, namely "Nuragic Sardinia, one northern Mediterranean source (e.g., individuals with group labels Lombardy, Tuscan, French, Basque, Spanish) and one eastern Mediterranean source (e.g., individuals with group labels Turkish-Jew, Libyan-Jew, Maltese, Tunisian-Jew, Moroccan-Jew, Lebanese, Druze, Cypriot, Jordanian, Palestinian)". Moreover, using a three-way model with Nuragic Sardinians, as well as "potential sources from various ancient samples that are representative of different regions of the Mediterranean", it was determined that "models with the largest p-values return fractions of Nuragic ancestry that are close to, or higher than 50%". North African ancestry among present-day Sardinians was found to be "negligible".<ref>{{cite web |last1=Marcus et al. (2020) |title=Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia |url=https://www.nature.com/articles/s41467-020-14523-6 |publisher=[[Nature Communications]] |access-date=9 December 2023}}</ref>
[[File:Figure 6.jpg|thumb|Outgroup f3 statistics of the form f3(San; Stuttgart, X), where X is a population across the merged dataset of Sardinia and Human Origins Array data. Higher f3 values suggest larger shared drift between a pair of populations]]
A study published in [[ScienceDirect]] in 2022, analysing the genetic structure of present-day Greek, and Italian populations, confirmed the Sardinians' status as an outlier in the Italian gene pool, stating that "Modern Italians, with the exception of Sardinians, are very different from the Mesolithic, Neolithic and Bronze Age individuals from the same area, with some resemblance only in Iron Age samples." In a four-way modelling with [[Anatolian Neolithic Farmers]] (Anatolia_N), Western European Hunter-Gatherers (WHG), Neolithic samples from the [[Iranian Plateau]] (Iran_N), and [[Eastern Hunter-Gatherers|Eastern European Hunter-Gatherers]] (EHG), Sardinians stood out by having notably more Anatolia_N-related ancestry, ~ 71% to be precise. Additionally, they were found to have ~ 18% Iran_N-related ancestry, whereas the remaining populations examined all had ~ 29 to 36% of this component. A different modelling using Neolithic Europeans (Europe_EN), Western Steppe Herders (Steppe_EMBA), and Iran_N saw "a sharp decrease in Iran_N contribution (from ~ 10 to 26%), due to the fact that a substantial proportion of Iran Neolithic-like ancestry might have arrived in the continent with Steppe Pastoralists" - a development Sardinians were seemingly less affected by than their neighbours. Additionally, Sardinians, along with samples from [[Lombardy]], and [[Tuscany]], were found to need the addition of WHG as a fourth source, indicating an excess of WHG with respect of Europe_EN.<ref>{{cite web |last1=Raveane et al. (2022) |title=Assessing temporal and geographic contacts across the Adriatic Sea through the analysis of genome-wide data from Southern Italy |url=https://www.sciencedirect.com/science/article/pii/S0888754322001501 |publisher=[[ScienceDirect]] |access-date=9 December 2023}}</ref>

Sardinians as a whole are not simply a homogeneous genetic population: several studies have found some differences among the various villages and sub-regions of the island.<ref>[http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004654 High Differentiation among Eight Villages in a Secluded Area of Sardinia Revealed by Genome-Wide High Density SNPs Analysis]</ref><ref>[https://www.mdpi.com/1422-0067/20/22/5763/htm Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case, International Journal of Molecular Sciences]</ref> In this regard, the mountainous area of [[Province of Ogliastra|Ogliastra]] (part of the wider region of [[Barbagia]]) is more distant from the rest of Europe and the Mediterranean than other Sardinian sub-regions located in the plains and in the coastal areas.<ref>[http://www.nature.com/ejhg/journal/v20/n11/full/ejhg201265a.html Genome-wide scan with nearly 700 000 SNPs in two Sardinian sub-populations suggests some regions as candidate targets for positive selection]</ref> This occurs in part because these more accessible areas show the highest genetic influxes of Bronze Age [[Pontic steppe|steppe]], Iranian farmer-related and North African ancestries in Sardinia, although still moderate in comparison to the predominant Neolithic farmer ancestry. By contrast, the more isolated area of Ogliastra retains the highest amount of earlier Mesolithic and Neolithic ancestry on the island.<ref name="ReferenceA" /><ref name="Marcus" /><ref name="The spread of steppe and Iranian-re" />

According to a study released in 2014, the [[genetic diversity]] among some Sardinian individuals from different regions of the island is between 7 and 30 times higher than the one found among other [[Ethnic groups in Europe|European ethnicities]] living thousands kilometers away from each other, like [[Spaniards]] and [[Romanians]].<ref>[http://www.unionesarda.it/articolo/cronaca_sardegna/2014/01/09/il_dna_sardo_il_pi_vario_d_europa_ricerca_sugli_abitanti_di_benetutti-6-348952.html Il Dna sardo è il più vario d'Europa Ricerca sugli abitanti di Benetutti – Unione Sarda]</ref> A similar phenomenon is commonly found in other isolated populations, like the [[Ladin people|Ladin groups]] from the Italian region of [[Veneto]] and in the [[Alps|Alpine]] area,<ref>[http://www.uniroma1.it/sites/default/files/allegati_news/segnalazione%20media_0.pdf Italiani, i più ricchi in Europa … di diversità genetica – Uniroma]</ref><ref>[http://www.repubblica.it/scienze/2014/01/09/news/italiani_popolo_pi_ricco_di_diversit_genetica_in_europa-75495329/ Gli italiani sono il popolo con la varietà genetica più ricca d'Europa – La Repubblica]</ref> where the local orography did not facilitate intraregional communications. However, despite a high degree of interindividual genetic differentiation being detected on multiple occasions, other studies have also stated that such variability does not occur among the main macro-regions of the island: a Sardinian region like the [[Barbagia]] has been proven not to be significantly different from the regions on the coast, like the area of [[Cagliari]] and [[Oristano]].<ref name="CuccaFrancesco" /> A study by Contu et al. (2008) found a relatively high degree of genetic homogeneity between Sardinian individuals from three different regions of the island: the northernmost area ([[Tempio]], [[Gallura]]), a central zone ([[Sorgono]], [[Barbagia]] of Mandrolisai) and the southernmost area ([[Cagliari]], [[Campidano]]).<ref>D. Contu, L. Morelli, F. Santoni, J.W. Foster, P. Francalacci, F. Cucca (2008). "Y-chromosome based evidence for pre-neolithic origin of the genetically homogenous but diverse Sardinian population; inference for association scans". PLOS ONE, Jan 9, 3(1): e1430</ref> Other studies have suggested again a certain degree of homogeneity within the Sardinian population.<ref>{{cite journal|title=An Overview of the Genetic Structure within the Italian Population from Genome-Wide Data|year=2012|doi=10.1371/journal.pone.0043759|journal=PLOS ONE|last1=Di Gaetano|first1=Cornelia|last2=Voglino|first2=Floriana|last3=Guarrera|first3=Simonetta|last4=Fiorito|first4=Giovanni|last5=Rosa|first5=Fabio|last6=Di Blasio|first6=Anna Maria|last7=Manzini|first7=Paola|last8=Dianzani|first8=Irma|last9=Betti|first9=Marta|last10=Cusi|first10=Daniele|last11=Frau|first11=Francesca|last12=Barlassina|first12=Cristina|last13=Mirabelli|first13=Dario|last14=Magnani|first14=Corrado|last15=Glorioso|first15=Nicola|last16=Bonassi|first16=Stefano|last17=Piazza|first17=Alberto|last18=Matullo|first18=Giuseppe|volume=7|issue=9|pages=e43759|pmid=22984441|pmc=3440425|bibcode=2012PLoSO...743759D|doi-access=free}}</ref><ref>{{cite journal| pmc=3961211 | pmid=24651212 | doi=10.1371/journal.pone.0091237 | volume=9 | issue=3 | title=Sardinians genetic background explained by runs of homozygosity and genomic regions under positive selection | year=2014 | journal=PLOS ONE | page=e91237 | last1 = Di Gaetano | first1 = C | last2 = Fiorito | first2 = G | last3 = Ortu | first3 = MF | last4 = Rosa | first4 = F | last5 = Guarrera | first5 = S | last6 = Pardini | first6 = B | last7 = Cusi | first7 = D | last8 = Frau | first8 = F | last9 = Barlassina | first9 = C | last10 = Troffa | first10 = C | last11 = Argiolas | first11 = G | last12 = Zaninello | first12 = R | last13 = Fresu | first13 = G | last14 = Glorioso | first14 = N | last15 = Piazza | first15 = A | last16 = Matullo | first16 = G| bibcode=2014PLoSO...991237D | doi-access=free }}</ref>

The 2015 SardiNIA study showed, by using the [[Fixation index|''F<sub>ST</sub>'']] differentiation statistic, a clear genetic differentiation between Sardinians (whole genome sequence of 2120 individuals from across the island and especially the [[Lanusei]] valley) and populations from the Italian peninsula (1000 genomes), and reported an even more significant amount of difference between the Sardinians from the above-mentioned Lanusei valley (in the mountainous [[Barbagia]] region) and the other European populations. This pattern of differentiation is also evident in the lengths for [[haplotypes]] surrounding rare variants [[Locus (genetics)|loci]], with a similar haplotype length for Sardinian populations and shorter length for populations with low grade of common ancestry.<ref>{{cite journal|author=Sidore, C., y colaboradores |title=Genome sequencing elucidates Sardinian genetic architecture and augments association analyses for lipid and blood inflammatory markers |year=2015 |journal=Nature Genetics |volume=47 |issue=11 |pages=1272–1281 |doi=10.1038/ng.3368 |pmid=26366554 |pmc=4627508}}</ref>

===Y-DNA and mtDNA studies===
[[File:Distribution Haplogroup I Y-DNA.svg|thumb|Distribution of Haplogroup I]]
The most common [[Y-DNA haplogroups]] among the Sardinian males, comprising ~70% of the population, are, in descending order, [[Haplogroup I-M438|I2]] (particularly I2a1a-M26), [[Haplogroup R-M269|R1b-M269]] and [[Haplogroup G-M201|G2a]].<ref>Paolo Francalacci et al.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500864/ Low-Pass DNA Sequencing of 1200 Sardinians Reconstructs European Y-Chromosome Phylogeny], 2013</ref> They are found respectively in the [[Western Hunter-Gatherers]], [[Western Steppe Herders]], and [[Early European Farmers]].

As in the rest of [[Europe]], the most common [[Human mitochondrial DNA haplogroup|mitochondrial DNA haplogroup]] is [[Haplogroup H (mtDNA)|H]].

===Conclusions===
In conclusion, it can therefore be stated that the Sardinian genes fit within the European gene pool, in particular [[Western Europe]]<ref>A. Raveane et al. ,Population structure of modern-day Italians reveals patterns of ancient and archaic ancestries in Southern Europe.Sci.Adv.5,eaaw3492(2019).[https://www.science.org/doi/full/10.1126/sciadv.aaw3492?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org#tab-citations DOI:10.1126/sciadv.aaw3492]</ref>, with major differences however in terms of:

*'''gene frequencies''' (mostly due to founder effect and random [[genetic drift]]). For example, the I2a1(M26) haplotype of the Y chromosome, also present in the [[Iberian peninsula]] and in France (19% in [[Castile]], 8% in [[Béarn]] and 6% among the Basques<ref name=Rootsi>AA.VV., [https://www.sciencedirect.com/science/article/pii/S0002929707620023 Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe]</ref>) has frequencies of up to over 40% in Sardinia.<ref>{{cita testo|url=https://www.nature.com/ejhg/journal/v11/n10/full/5201040a.html|titolo=European Journal of Human Genetics - From surnames to the history of Y chromosomes: the Sardinian population as a paradigm<!-- Titolo generato automaticamente -->}}</ref> The high frequency of this haplotype among Sardinians would be due to a prehistoric migration of peoples originating from [[continental Europe]] towards Sardinia, perhaps from the [[Pyrenees]] region<ref name="Rootsi"/> or, alternatively, from [[Tuscany]], through the [[Elba]] island and [[Corsica]].<ref>{{Cita web|url=https://www.mdpi.com/1422-0067/20/22/5763#B15-ijms-20-05763|titolo=Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case|accesso=30 settembre 2023}}</ref> [[Haplogroup I]], present in Europe since the [[Upper Paleolithic]]<ref>{{Cita pubblicazione|cognome1=Fu|nome1=Qiaomei|cognome2=Posth|nome2=Cosimo|cognome3=Hajdinjak|nome3=Mateja|cognome4=Petr|nome4=Martin|cognome5=Mallick|nome5=Swapan|cognome6=Fernandes|nome6=Daniel|cognome7=Furtwängler|nome7=Anja|cognome8=Haak|nome8=Wolfgang|cognome9=Meyer|nome9=Matthias|anno=2016|titolo=The genetic history of Ice Age Europe|rivista=Nature|lingua=en|volume=534|numero=7606|pp=200–205|doi=10.1038/nature17993|issn=0028-0836|pmc=4943878|pmid=27135931|bibcode=2016Natur.534..200F}}</ref>, is found among modern Europeans mainly in the Sardinian population, but in similar percentages also among those of the [[Western Balkans]] and [[Scandinavia]].

*presence of '''Sardinian-specific haplotype''' (attributable to mutations that occurred on the island given the long time that has passed from the foundation to today). For example, the R-M18 haplotype is exclusive to Sardinia and originates from the acquisition of a mutation from the more ancient R-M173 haplogroup; there is also the mitochondrial line U5b3a1a, almost exclusive to Sardinia but originating from [[Provence]].

*low incidence of the ANE ([[Ancient North Eurasian]]) autosomal component, widespread in most Eurasian populations and among Native Americans; constitutes approximately 10-20% of the genetic ancestry of current Europeans, in Sardinia approximately 5%.<ref>AA.VV., Ancient human genomes suggest three ancestral populations for present-day Europeans</ref> This component, which can be linked to some [[Siberia]]n Paleolithic populations including those of the [[Mal'ta-Buret' culture]], would have arrived in Western Europe from the East starting from the Chalcolithic period through the migration of new populations called Western steppe herders. The genetic contribution of the peoples of the Pontic-Caspian steppes, who are believed to have introduced the Indo-European languages ​​to Europe, is more relevant in Sardinia in the coastal and sub-coastal regions than in the mountainous region of [[Gennargentu]].<ref>Charleston W.K. Chiang et al., 2018, [https://www.nature.com/articles/s41588-018-0215-8 Genomic history of the Sardinian population]</ref>

==Commons genetic diseases==
*[[Type 1 diabetes]]
*[[Wilson's disease]]
*[[Multiple sclerosis]]
*[[Thalassemia]]
*[[Autoimmune polyendocrine syndrome type 1]]

==Longevity==
{{Main|Blue zone}}
In Sardinia the presence of numerous centenarians has been noted (in July 2007 there were more than 330), on average around 22 per one hundred thousand inhabitants, compared to an average of between 8 and 10 in other parts of the world.<ref>Pier Giorgio Pinna, {{cita testo|url=http://www.unica.it/pub/7/show.jsp?id=3495&iso=471&is=7|titolo=Nell'isola dei centenari può succedere di tutto}}, [[La Nuova Sardegna]], 26 luglio 2007</ref> This ratio appears to be growing over time, since in the period '97-'99 the average was 13.5 over centenarians, and in 2000 it had risen to 19.<ref>Celestino Tabasso, {{cita testo|url=http://www.unica.it/pub/7/show.jsp?id=544&iso=111&is=7|titolo=Akea: un microscopio puntato sul mistero dei centenari sardi}}, [[L'Unione Sarda]], 12 maggio 2006.</ref>

Internal areas with a high concentration of long-lived people have been identified, and it has been discovered that the male/female ratio over one hundred years old in Sardinia is very different from that present elsewhere. If in the rest of Italy and in the West the ratio is 1 to 4, if not even 1 to 7, on the island it is generally below 1 to 2, becoming equal in the internal areas.<ref>Giancarlo Bulla, {{cita testo|url=http://www.unica.it/pub/7/show.jsp?id=558&iso=111&is=7|titolo=Una terra di ultracentenari}}, [[La Nuova Sardegna]], 14 maggio 2006.</ref>

Many explanations have been formulated for this particularity, such as quality of life or a particular diet, but mainly scholars are interested in analyzing specific genetic factors that interact in conjunction with environmental factors.

The island boasts some records:

*the oldest man in the world, certified by the Guinness Book of Records 2001. Antonio Todde (called Tziu Antoni), born in [[Tiana]] (NU) on 22 January 1889, passed away on 3 January 2002, a few weeks before his 113th birthday ; he attributed his longevity to the glass of good red wine he drank every day.<ref>{{Cita testo|lingua=en|url=http://news.bbc.co.uk/1/hi/world/europe/1744097.stm|titolo=World's 'oldest man' dies}}, [[British Broadcasting Corporation|BBC News]], 5 gennaio 2002.</ref>
*the oldest man in Europe, and third in the world, in 2003. Giovanni Frau, born in [[Orroli]] (CA) on 29 December 1890, passed away on 19/06/2003 at the age of 112.<ref>vedi i {{cita testo|url=http://www.comuneorroli.it/sito/centenari.htm|titolo=centenari di Orroli|urlarchivio=https://web.archive.org/web/20090428105932/http://www.comuneorroli.it/sito/centenari.htm }}</ref>

==Notes==
<references/>

Revision as of 06:31, 10 January 2024

The Genetic history of Sardinia consists of the study of the gene pool of the islanders with two main objectives. The first is purely scientific and cultural and is to reconstruct the natural history of the population. It consists in understanding the extent, timing and methods of the foundation together with the subsequent or concomitant demographic and evolutionary dynamics. The other is instead applicative and has the aim of understanding the genetic causes of some pathologies by exploiting some peculiarities of the Sardinian population, which make it ideal for studies involving the use of genetic isolates.

The geographical position of Sardinia and the mountainousness of its territory have meant that particular anthropological and genetic characteristics have been created in the Sardinian population, due to phenomena such as isolation, endogamy and evolutionary processes such as genetic drift, in similarly to other European populations such as the Basques, Lapps and Icelanders

The high genetic variability implies a significant number of founding lines. Archeology indicates that the actual size of the Sardinian population was significant compared to other contemporary geographical areas. Great demographic crises, such as those caused by plague epidemics, have not been able to affect the original structure of the population.

Studies

Autosomal studies

Recent comparisons between the Sardinians' genome and that of some individuals from the Neolithic and the early Chalcolithic, who lived in the Alpine (Oetzi), German, and Hungarian regions, showed considerable similarities between the two populations, while at the same time consistent differences between the prehistoric samples and the present inhabitants of the same geographical areas were noted.[1] From this it can be deduced that, while central and northern Europe have undergone significant demographic changes due to post-Neolithic migrations, presumably from the eastern periphery of Europe (Pontic–Caspian steppe), Southern Europe and Sardinia in particular were affected less; Sardinians appear to be the population that has best preserved the Neolithic legacy of Western Europe.[2][3][4][5][6][7][8][9][1][10]

A 2020 study by Fernandes et al. estimated that the current Sardinian genome derives roughly 62.5% from Neolithic Early European Farmers (EEF), 9.7% from the Mesolithic Western Hunter-Gatherers (WHG), 13.9% from ancestry related to Neolithic Iranians of Ganj Dareh (or also Caucasus-related ancestry), 10.6% from the Bronze Age Western Steppe Herders (WSH) of the Yamnaya culture and, lastly, 3.4% from Late Neolithic Moroccans (partly of European origin).[11][12] Fernandes concluded that: "Major immigration into Sardinia began in the first millennium BC and, at present, no more than 56–62% of Sardinian ancestry is from its first farmers. This value is lower than previous estimates, highlighting that Sardinia, similar to every other region in Europe, has been a stage for major movement and mixtures of people".[11]

Three-way admixture model of present-day Sardinians by pre-2016 province

Another study from 2020 also found that the present-day Sardinian genome was shaped by immigration from the Iron Age onwards, which can be modelled well using three source populations, namely "Nuragic Sardinia, one northern Mediterranean source (e.g., individuals with group labels Lombardy, Tuscan, French, Basque, Spanish) and one eastern Mediterranean source (e.g., individuals with group labels Turkish-Jew, Libyan-Jew, Maltese, Tunisian-Jew, Moroccan-Jew, Lebanese, Druze, Cypriot, Jordanian, Palestinian)". Moreover, using a three-way model with Nuragic Sardinians, as well as "potential sources from various ancient samples that are representative of different regions of the Mediterranean", it was determined that "models with the largest p-values return fractions of Nuragic ancestry that are close to, or higher than 50%". North African ancestry among present-day Sardinians was found to be "negligible".[13]

Outgroup f3 statistics of the form f3(San; Stuttgart, X), where X is a population across the merged dataset of Sardinia and Human Origins Array data. Higher f3 values suggest larger shared drift between a pair of populations

A study published in ScienceDirect in 2022, analysing the genetic structure of present-day Greek, and Italian populations, confirmed the Sardinians' status as an outlier in the Italian gene pool, stating that "Modern Italians, with the exception of Sardinians, are very different from the Mesolithic, Neolithic and Bronze Age individuals from the same area, with some resemblance only in Iron Age samples." In a four-way modelling with Anatolian Neolithic Farmers (Anatolia_N), Western European Hunter-Gatherers (WHG), Neolithic samples from the Iranian Plateau (Iran_N), and Eastern European Hunter-Gatherers (EHG), Sardinians stood out by having notably more Anatolia_N-related ancestry, ~ 71% to be precise. Additionally, they were found to have ~ 18% Iran_N-related ancestry, whereas the remaining populations examined all had ~ 29 to 36% of this component. A different modelling using Neolithic Europeans (Europe_EN), Western Steppe Herders (Steppe_EMBA), and Iran_N saw "a sharp decrease in Iran_N contribution (from ~ 10 to 26%), due to the fact that a substantial proportion of Iran Neolithic-like ancestry might have arrived in the continent with Steppe Pastoralists" - a development Sardinians were seemingly less affected by than their neighbours. Additionally, Sardinians, along with samples from Lombardy, and Tuscany, were found to need the addition of WHG as a fourth source, indicating an excess of WHG with respect of Europe_EN.[14]

Sardinians as a whole are not simply a homogeneous genetic population: several studies have found some differences among the various villages and sub-regions of the island.[15][16] In this regard, the mountainous area of Ogliastra (part of the wider region of Barbagia) is more distant from the rest of Europe and the Mediterranean than other Sardinian sub-regions located in the plains and in the coastal areas.[17] This occurs in part because these more accessible areas show the highest genetic influxes of Bronze Age steppe, Iranian farmer-related and North African ancestries in Sardinia, although still moderate in comparison to the predominant Neolithic farmer ancestry. By contrast, the more isolated area of Ogliastra retains the highest amount of earlier Mesolithic and Neolithic ancestry on the island.[18][19][20]

According to a study released in 2014, the genetic diversity among some Sardinian individuals from different regions of the island is between 7 and 30 times higher than the one found among other European ethnicities living thousands kilometers away from each other, like Spaniards and Romanians.[21] A similar phenomenon is commonly found in other isolated populations, like the Ladin groups from the Italian region of Veneto and in the Alpine area,[22][23] where the local orography did not facilitate intraregional communications. However, despite a high degree of interindividual genetic differentiation being detected on multiple occasions, other studies have also stated that such variability does not occur among the main macro-regions of the island: a Sardinian region like the Barbagia has been proven not to be significantly different from the regions on the coast, like the area of Cagliari and Oristano.[24] A study by Contu et al. (2008) found a relatively high degree of genetic homogeneity between Sardinian individuals from three different regions of the island: the northernmost area (Tempio, Gallura), a central zone (Sorgono, Barbagia of Mandrolisai) and the southernmost area (Cagliari, Campidano).[25] Other studies have suggested again a certain degree of homogeneity within the Sardinian population.[26][27]

The 2015 SardiNIA study showed, by using the FST differentiation statistic, a clear genetic differentiation between Sardinians (whole genome sequence of 2120 individuals from across the island and especially the Lanusei valley) and populations from the Italian peninsula (1000 genomes), and reported an even more significant amount of difference between the Sardinians from the above-mentioned Lanusei valley (in the mountainous Barbagia region) and the other European populations. This pattern of differentiation is also evident in the lengths for haplotypes surrounding rare variants loci, with a similar haplotype length for Sardinian populations and shorter length for populations with low grade of common ancestry.[28]

Y-DNA and mtDNA studies

Distribution of Haplogroup I

The most common Y-DNA haplogroups among the Sardinian males, comprising ~70% of the population, are, in descending order, I2 (particularly I2a1a-M26), R1b-M269 and G2a.[29] They are found respectively in the Western Hunter-Gatherers, Western Steppe Herders, and Early European Farmers.

As in the rest of Europe, the most common mitochondrial DNA haplogroup is H.

Conclusions

In conclusion, it can therefore be stated that the Sardinian genes fit within the European gene pool, in particular Western Europe[30], with major differences however in terms of:

  • presence of Sardinian-specific haplotype (attributable to mutations that occurred on the island given the long time that has passed from the foundation to today). For example, the R-M18 haplotype is exclusive to Sardinia and originates from the acquisition of a mutation from the more ancient R-M173 haplogroup; there is also the mitochondrial line U5b3a1a, almost exclusive to Sardinia but originating from Provence.
  • low incidence of the ANE (Ancient North Eurasian) autosomal component, widespread in most Eurasian populations and among Native Americans; constitutes approximately 10-20% of the genetic ancestry of current Europeans, in Sardinia approximately 5%.[35] This component, which can be linked to some Siberian Paleolithic populations including those of the Mal'ta-Buret' culture, would have arrived in Western Europe from the East starting from the Chalcolithic period through the migration of new populations called Western steppe herders. The genetic contribution of the peoples of the Pontic-Caspian steppes, who are believed to have introduced the Indo-European languages ​​to Europe, is more relevant in Sardinia in the coastal and sub-coastal regions than in the mountainous region of Gennargentu.[36]

Commons genetic diseases

Longevity

Main article: Blue zone

In Sardinia the presence of numerous centenarians has been noted (in July 2007 there were more than 330), on average around 22 per one hundred thousand inhabitants, compared to an average of between 8 and 10 in other parts of the world.[37] This ratio appears to be growing over time, since in the period '97-'99 the average was 13.5 over centenarians, and in 2000 it had risen to 19.[38]

Internal areas with a high concentration of long-lived people have been identified, and it has been discovered that the male/female ratio over one hundred years old in Sardinia is very different from that present elsewhere. If in the rest of Italy and in the West the ratio is 1 to 4, if not even 1 to 7, on the island it is generally below 1 to 2, becoming equal in the internal areas.[39]

Many explanations have been formulated for this particularity, such as quality of life or a particular diet, but mainly scholars are interested in analyzing specific genetic factors that interact in conjunction with environmental factors.

The island boasts some records:

  • the oldest man in the world, certified by the Guinness Book of Records 2001. Antonio Todde (called Tziu Antoni), born in Tiana (NU) on 22 January 1889, passed away on 3 January 2002, a few weeks before his 113th birthday ; he attributed his longevity to the glass of good red wine he drank every day.[40]
  • the oldest man in Europe, and third in the world, in 2003. Giovanni Frau, born in Orroli (CA) on 29 December 1890, passed away on 19/06/2003 at the age of 112.[41]

Notes

  1. ^ a b Genome flux and stasis in a five millennium transect of European prehistory
  2. ^ Keller at al 2011, Nature
  3. ^ Mathieson et al 2015, Nature
  4. ^ supp. info (p.16)
  5. ^ A Common Genetic Origin for Early Farmers from Mediterranean Cardial and Central European LBK Cultures, Olalde et al 2015, Molecular Biology and Evolution
  6. ^ Gamba et al 2014, Genome flux and stasis in a five millennium transect of European prehistory, Nature
  7. ^ Omrak et al 2016, Genomic Evidence Establishes Anatolia as the Source of the European Neolithic Gene Pool, Current Biology, Volume 26, Issue 2, p270–275, 25 January 2016
  8. ^ Haak et al 2015, Massive migration from the steppe was a source for Indo-European languages in Europe
  9. ^ supp. info (p.120)
  10. ^ Reference Populations Genographic Project. National Geographic
  11. ^ a b Fernandes, Daniel M. (24 February 2020). "The Spread of Steppe and Iranian Related Ancestry in the Islands of the Western Mediterranean". Nature Ecology & Evolution. 4 (3): 334–345. Bibcode:2020NatEE...4..334F. doi:10.1038/s41559-020-1102-0. PMC 7080320. PMID 32094539.
  12. ^ Supplementary information p.29
  13. ^ Marcus et al. (2020). "Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia". Nature Communications. Retrieved 9 December 2023.{{cite web}}: CS1 maint: numeric names: authors list (link)
  14. ^ Raveane et al. (2022). "Assessing temporal and geographic contacts across the Adriatic Sea through the analysis of genome-wide data from Southern Italy". ScienceDirect. Retrieved 9 December 2023.{{cite web}}: CS1 maint: numeric names: authors list (link)
  15. ^ High Differentiation among Eight Villages in a Secluded Area of Sardinia Revealed by Genome-Wide High Density SNPs Analysis
  16. ^ Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case, International Journal of Molecular Sciences
  17. ^ Genome-wide scan with nearly 700 000 SNPs in two Sardinian sub-populations suggests some regions as candidate targets for positive selection
  18. ^ Cite error: The named reference ReferenceA was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Marcus was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference The spread of steppe and Iranian-re was invoked but never defined (see the help page).
  21. ^ Il Dna sardo è il più vario d'Europa Ricerca sugli abitanti di Benetutti – Unione Sarda
  22. ^ Italiani, i più ricchi in Europa … di diversità genetica – Uniroma
  23. ^ Gli italiani sono il popolo con la varietà genetica più ricca d'Europa – La Repubblica
  24. ^ Cite error: The named reference CuccaFrancesco was invoked but never defined (see the help page).
  25. ^ D. Contu, L. Morelli, F. Santoni, J.W. Foster, P. Francalacci, F. Cucca (2008). "Y-chromosome based evidence for pre-neolithic origin of the genetically homogenous but diverse Sardinian population; inference for association scans". PLOS ONE, Jan 9, 3(1): e1430
  26. ^ Di Gaetano, Cornelia; Voglino, Floriana; Guarrera, Simonetta; Fiorito, Giovanni; Rosa, Fabio; Di Blasio, Anna Maria; Manzini, Paola; Dianzani, Irma; Betti, Marta; Cusi, Daniele; Frau, Francesca; Barlassina, Cristina; Mirabelli, Dario; Magnani, Corrado; Glorioso, Nicola; Bonassi, Stefano; Piazza, Alberto; Matullo, Giuseppe (2012). "An Overview of the Genetic Structure within the Italian Population from Genome-Wide Data". PLOS ONE. 7 (9): e43759. Bibcode:2012PLoSO...743759D. doi:10.1371/journal.pone.0043759. PMC 3440425. PMID 22984441.
  27. ^ Di Gaetano, C; Fiorito, G; Ortu, MF; Rosa, F; Guarrera, S; Pardini, B; Cusi, D; Frau, F; Barlassina, C; Troffa, C; Argiolas, G; Zaninello, R; Fresu, G; Glorioso, N; Piazza, A; Matullo, G (2014). "Sardinians genetic background explained by runs of homozygosity and genomic regions under positive selection". PLOS ONE. 9 (3): e91237. Bibcode:2014PLoSO...991237D. doi:10.1371/journal.pone.0091237. PMC 3961211. PMID 24651212.
  28. ^ Sidore, C., y colaboradores (2015). "Genome sequencing elucidates Sardinian genetic architecture and augments association analyses for lipid and blood inflammatory markers". Nature Genetics. 47 (11): 1272–1281. doi:10.1038/ng.3368. PMC 4627508. PMID 26366554.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  29. ^ Paolo Francalacci et al.Low-Pass DNA Sequencing of 1200 Sardinians Reconstructs European Y-Chromosome Phylogeny, 2013
  30. ^ A. Raveane et al. ,Population structure of modern-day Italians reveals patterns of ancient and archaic ancestries in Southern Europe.Sci.Adv.5,eaaw3492(2019).DOI:10.1126/sciadv.aaw3492
  31. ^ a b AA.VV., Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe
  32. ^ https://www.nature.com/ejhg/journal/v11/n10/full/5201040a.html {{citation}}: Missing or empty |title= (help); Unknown parameter |titolo= ignored (|title= suggested) (help)
  33. ^ "Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case". Retrieved 30 September 2023.
  34. ^ Fu, Qiaomei; Posth, Cosimo; Hajdinjak, Mateja; Petr, Martin; Mallick, Swapan; Fernandes, Daniel; Furtwängler, Anja; Haak, Wolfgang; Meyer, Matthias (2016). "The genetic history of Ice Age Europe". Nature. 534 (7606): 200–205. Bibcode:2016Natur.534..200F. doi:10.1038/nature17993. ISSN 0028-0836. PMC 4943878. PMID 27135931.
  35. ^ AA.VV., Ancient human genomes suggest three ancestral populations for present-day Europeans
  36. ^ Charleston W.K. Chiang et al., 2018, Genomic history of the Sardinian population
  37. ^ Pier Giorgio Pinna, http://www.unica.it/pub/7/show.jsp?id=3495&iso=471&is=7 {{citation}}: Missing or empty |title= (help); Unknown parameter |titolo= ignored (|title= suggested) (help), La Nuova Sardegna, 26 luglio 2007
  38. ^ Celestino Tabasso, http://www.unica.it/pub/7/show.jsp?id=544&iso=111&is=7 {{citation}}: Missing or empty |title= (help); Unknown parameter |titolo= ignored (|title= suggested) (help), L'Unione Sarda, 12 maggio 2006.
  39. ^ Giancarlo Bulla, http://www.unica.it/pub/7/show.jsp?id=558&iso=111&is=7 {{citation}}: Missing or empty |title= (help); Unknown parameter |titolo= ignored (|title= suggested) (help), La Nuova Sardegna, 14 maggio 2006.
  40. ^ http://news.bbc.co.uk/1/hi/world/europe/1744097.stm {{citation}}: Missing or empty |title= (help); Unknown parameter |lingua= ignored (|language= suggested) (help); Unknown parameter |titolo= ignored (|title= suggested) (help), BBC News, 5 gennaio 2002.
  41. ^ vedi i http://www.comuneorroli.it/sito/centenari.htm {{citation}}: External link in |urlarchivio= (help); Missing or empty |title= (help); Unknown parameter |titolo= ignored (|title= suggested) (help); Unknown parameter |urlarchivio= ignored (|archive-url= suggested) (help)
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