Sardinians Genetic Background Explained by Runs of Homozygosity and Genomic Regions under Positive Selection

Cornelia Di Gaetano, Giovanni Fiorito, Maria Francesca Ortu, Fabio Rosa, Simonetta Guarrera, Barbara Pardini, Daniele Cusi, Francesca Frau, Cristina Barlassina, Chiara Troffa, Giuseppe Argiolas, Roberta Zaninello (+5 others)
2014 PLoS ONE  
The peculiar position of Sardinia in the Mediterranean sea has rendered its population an interesting biogeographical isolate. The aim of this study was to investigate the genetic population structure, as well as to estimate Runs of Homozygosity and regions under positive selection, using about 1.2 million single nucleotide polymorphisms genotyped in 1077 Sardinian individuals. Using four different methods -fixation index, inflation factor, principal component analysis and ancestry estimation
more » ... e were able to highlight, as expected for a genetic isolate, the high internal homogeneity of the island. Sardinians showed a higher percentage of genome covered by RoHs.0.5 Mb (F RoH%0.5 ) when compared to peninsular Italians, with the only exception of the area surrounding Alghero. We furthermore identified 9 genomic regions showing signs of positive selection and, we re-captured many previously inferred signals. Other regions harbor novel candidate genes for positive selection, like TMEM252, or regions containing long non coding RNA. With the present study we confirmed the high genetic homogeneity of Sardinia that may be explained by the shared ancestry combined with the action of evolutionary forces.
doi:10.1371/journal.pone.0091237 pmid:24651212 pmcid:PMC3961211 fatcat:xqxjhcms4bbyhmau35xg7esroi