A genome-wide portrait of Italy
Résumé
We performed a clustering model for K = 218 using ADMIXTURE [7] on 1,588 individuals belonging to the 20 italian regions combined with ~300 worldwide populations. The results are shown in Fig. 3. We identified five major ancestral components: blue, yellow, gray, green and violet. Overall, they are distributed homogeneously within regions, along a NorthSouth cline for entire Italian peninsula, with the exception of Sardinia. The blue component is present in all the Italian regions with high frequencies in Sardinia remarking its genetic peculiarity related to its isolation history and ancestry. The yellow component has high frequencies in the regions of Northern Italy, decreasing values in the Central regions, until reaching low frequencies in Southern Italy. Its distribution is modal in Northern and Central Europe reflecting their genetic affinity with neighbouring regions, as already reported in our f3 statistics analysis. An opposite distribution is evident in the violet component, in which highest frequencies are observed in the South with decreasing values in Northern Italy. This component is found AT high frequencies in North Africa and might represent the legacy of the Arab rule in Southern Italy. Finally, the grey and the green components, modal in Caucasian and Middle Eastern groups, could be the results of recent interactions between Italy and Eastern Europe or Western Asia.
The PC analysis in Fig. 4 is a summary of the genetic variability of Italy compared to the one of the Europe. Italy is stretched between the Mediterranean area (CyprusCYP) and West/Central Europe (SpainSPA and France FRA) with high affinity with Portugal, Switzerland and Corsica. Interestingly, we noticed a partial overlap between France and Valle d'Aosta, while individuals from Friuli Venezia Giulia are spread toward the Central Balkanic area. The Sardinian and Basque are wellknown examples of genetically differentiated populations [8] and diverge clearly from the rest of the continental samples in our plot. Similarly to the distribution of the Italian populations, a NorthSouth cline of individuals from the Balkanic regions is observed, with populations in the South and North closer to Southern and Central Europe,respectively.
Domaines
Génétique humaine| Origine | Fichiers produits par l'(les) auteur(s) |
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