Genetic diversity and adaptability of native sheep breeds from different climatic zones

Abstract

To better understand the genetic architecture and adaptability of native sheep, 22 breeds were genotyped using ovine50K SNP chips. Eleven additional populations from open-source repositories were included. Cross population Extended Haplotype Homozygosity (XP-EHH) and Relative Scaled Haplotype Homozygosity (Rsb) haplotype-based approaches were used to identify genetic variations influencing the adaptation of local sheep breeds to different climatic zones. The results indicate that all breeds exhibited high but declining genetic diversity levels, with a larger proportion of genetic variation explained by development history and refined by geographical origin, as shown by principal component analysis and Neighbor Net graphs. Admixture analysis revealed high admixture levels in European and North African breeds. Using XP-EHH and Rsb methods, 371 genes were putatively under selection, with only nine common among all population pairs, highlighting unique adaptability. Most identified genes, including Interleukin (IL) and cluster differentiation (CD) gene families underlie immune responses, emphasizing their role in resilience to climate change effects. These findings support that indigenous sheep breeds have retained significant genetic diversity, but improper genetic management may threaten it. Additionally, the research emphasizes that indigenous sheep breeds’ unique adaptability to specific climatic zones makes them valuable genetic assets for developing climate-resilient breeds.