Susceptibility to complex diseases in Sardinian population explained by Runs of Homozygosity and genomic regions under positive selection

Aim:1)Confirm and detail the homogeneity of the Sardinian population at interregional level based on the analysis "genome-wide" through the use of "Runs of Homozygosity" (RoHS);2) infer the genetic history of the Sardinian population by estimating the level of genetic background of the common ancestry within the island and compare it to the Italian peninsula; 3)Identify indicators of positive selection.Methods:About single nucleotide polymorphisms (SNPs) genotyped in 1077 Sardinian individuals were used to investigate the genetic population structure, as well as to estimate RoH and Extended Haplotype Homozygosity regions. We used four different methods: fixation index, inflaction factor, multi-dimensional scaling and ancestry estimation. we were able to highlight, as expected from a genetic isolate, the high internal homogeneity of the island. Comparing Sardinia to mainland Italy through several classes of RoH.Conclusion:We confirmed the high genetic homogeneity of Sardinia and we have shown that the genome of the Sardinians has mean inbreeding coefficients which are higher than those of mainland Italians. Furthermore, the Sardinian’s genome still preserves traces of the elaborate demographic history of the island. In addition, we observed that some genomic regions showing signs of positive selection.