Purging of deleterious variants in Italian founder populations with extended autozygosity

Massimiliano Cocca, Marc Pybus, Pier Francesco Palamara, Erik Garrison, Michela Traglia, Cinzia F Sala, Sheila Ulivi, Yasin Memari, Anja Kolb-Kokocinski, Richard Durbin, Paolo Gasparini, Daniela Toniolo, Nicole Soranzo, Vincenza Colonna
doi: http://dx.doi.org/10.1101/022947

Purging through inbreeding defines the process through which deleterious alleles can be removed from populations by natural selection when exposed in homozygosis through the occurrence of consanguineous marriage. In this study we carried out low-read depth (4-10x) whole-genome sequencing in 568 individuals from three Italian founder populations, and compared it to data from other Italian and European populations from the 1000 Genomes Project. We show depletion of homozygous genotypes at potentially detrimental sites in the founder populations compared to outbred populations and observe patterns consistent with consanguinity driving the accelerated purging of highly deleterious mutations.