PSXVI-17 Estimation of inbreeding in local sheep breeds of west Asian and central Asian origin based on high-density SNP-genotypes

Abstract

Maintaining high levels of genetic diversity is a key factor of successful breeding of resilient, resistant to diseases and productive sheep. Prevention of inbreeding is of special importance in the mountainous hard-to-get habitats where gene flow is limited or absent. An assessment of inbreeding coefficients based only on pedigree information is not always correct. In addition, pedigree information is often missing for flocks of native sheep. In this regard, we performed a genomic assessment of inbreeding in 15 local sheep breeds inhabiting severe environments of Russia and neighboring Asian countries based on estimations of standardized multilocus heterozygosity (sMLH) and runs of homozygosity [F(ROH)]. For this study, we used SNP genotypes of twelve Russian local breeds (n = 316) and three Kyrgyz local breeds (n = 68), which were generated using Ovine Infinium® HD SNP BeadChip (Illumina, CA, USA). The sMLH values were calculated using R package inbreedR and visualized in R package ggplot2. The F(ROH) values were calculated using the R package detectRUNS by applying the consecutive runs method. Mean sMLH values were varied from 0.962 ± 0.006 in the Andean breed to 1.031 ± 0.002 in the Buryat breed and averaged to 1.001± 0.004. The least mean F(ROH) value was detected in the Mongolian breed (0.0043 ± 0.0009) while the greatest ones were observed in the Alai and Andean breeds (0.0364 ± 0.0049 and 0.0357 ± 0.0061, respectively). The strong negative correlations between sMLH and F(ROH) were detected for all of studied breeds (r2 = –0.8496, CI = –0.8752… –0.8192). The obtained data is relevant for control of inbreeding level in the populations and for future sustainable management of native fat-tailed sheep breeds. The study was funded by RSF No. 19-16-00070.