Genetic characterization of northeastern Italian population isolates in the context of broader European genetic diversity.

Tõnu Esko, Massimo Mezzavilla, Mari Nelis, Christelle Borel, Tadeusz Debniak, Eveliina Jakkula, Antonio Julia, Sena Karachanak, Andrey Khrunin, Peter Kisfali, Veronika Krulisova, Zita Aušrelé Kučinskiené, Karola Rehnström, Michela Traglia, Liene Nikitina-Zake, Fritz Zimprich, Stylianos E Antonarakis, Xavier Estivill, Damjan Glavač, Ivo Gut, Janis Klovins, Michael Krawczak, Vaidutis Kučinskas, Mark Lathrop, Milan Macek, Sara Marsal, Thomas Meitinger, Béla Melegh, Svetlana Limborska, Jan Lubinski, Aarno Paolotie, Stefan Schreiber, Draga Toncheva, Daniela Toniolo, H-Erich Wichmann, Alexander Zimprich, Mait Metspalu, Paolo Gasparini, Andres Metspalu, Pio D'Adamo
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European journal of human genetics
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Population genetic studies on European populations have highlighted Italy as one of genetically most diverse regions. This is possibly due to the country''s complex demographic history and large variability in terrain throughout the territory. This is the reason why Italy is enriched for population isolates, Sardinia being the best-known example. As the population isolates have a great potential in disease-causing genetic variants identification, we aimed to genetically characterize a region from northeastern Italy, which is known for isolated communities. Total of 1310 samples, collected from six geographically isolated villages, were genotyped at >145000 single-nucleotide polymorphism positions. Newly genotyped data were analyzed jointly with the available genome-wide data sets of individuals of European descent, including several population isolates. Despite the linguistic differences and geographical isolation the village populations still show the greatest genetic similarity to other Italian samples. The genetic isolation and small effective population size of the village populations is manifested by higher levels of genomic homozygosity and elevated linkage disequilibrium. These estimates become even more striking when the detected substructure is taken into account. The observed level of genetic isolation in Friuli-Venezia Giulia region is more extreme according to several measures of isolation compared with Sardinians, French Basques and northern Finns, thus proving the status of an isolate.