Genetic diversity and population structure estimation of Brazilian Somali sheep from pedigree data

Abstract

The aim of this study was to describe and analyze the genetic diversity and population structure of Brazilian Somali sheep using pedigree records. Pedigree data of 9,038 individuals born between 1972 and 2018 were analyzed for completeness, gene origin probability, average relationship coefficient (AR), inbreeding coefficient, and genetic conservation index (GCI), using ENDOG v4.8 software. A total of 69.59%, 56.43%, 48.64%, 42.77%, and 34.05% of the examined individuals had pedigrees in the first, second, third, fourth and fifth ancestry, respectively. The total number of founders and ancestors was 833 and 837, whereas the effective number of founders and ancestors was 26 and 22, respectively. The eight main ancestors explained 51.04% of the total genetic variability. The AR and average inbreeding coefficient were 4.05 and 8.74, respectively. The mean GCI was 4.08, ranging from 1.00 to 17.43; three individuals showed a GCI above 17. In conclusion, the Brazilian Somali sheep show considerably high inbreeding coefficients, particularly those individuals born within the last decades. In contrast, some individuals have a high proportion of effective founders in their pedigrees, which can be used strategically for maintaining the genetic diversity of the breed.