Study on the Genomic Basis of Adaptation in Salsk Sheep

This study investigates the genetic architecture of Salsk sheep-a long-established Russian Merino-type breed from the southern steppes-highlighting their broad genetic diversity, resilience to cold and drought, and dual-purpose (wool and meat) productivity as a unique gene pool shaped by natural and artificial selection. The study used data from 96 sheep. Genotyping was carried out on the Illumina Ovine Infinium^® HD BeadChip platform, and after filtering, 511,145 SNPs were retained. We assessed population structure and genetic diversity using principal component analysis (PCA), Fst, and linkage disequilibrium (LD) in comparison with four reference European breeds. To detect selection signatures, we employed a combination of complementary methods, including intra-population statistics (iHS, nSL, iHH12) and inter-population comparisons (XP-EHH). This integrated approach identified genomic regions under positive selection, reflecting the breed's evolutionary response to both natural and artificial selection pressures. Strong selection signals were detected in genes associated with production traits like fertility and growth (CCSER1, SOX6), as well as fundamental adaptive functions, including immune response (IL6R, NLRP1) and energy metabolism (ACSL5, FANCA). These results elucidate the genetic basis of the Salsk breed's high resilience and highlight its potential as a valuable genetic resource for improving this trait in other sheep populations.