Exploring climate adaptation in European Merino sheep: a landscape genomics approach

In the context of global climate change, it is important to better understand the genetic drivers of environmental adaptation in livestock. As sheep (Ovis aries) exhibit a multitude of local adaptations, they represent an ideal subject for the investigation of environmental adaptation within and between breeds. This is particularly relevant in the case of Merino and Merino-derived sheep, which are used globally for wool production. This study investigates the landscape genomics of 24 European Merino sheep populations, examining the associations between 50 K SNP chip genotyping data and 19 bioclimatic variables, predominantly related to precipitation and temperature. Following the implementation of quality control filtering, a dataset was obtained, comprising 38 381 single-nucleotide polymorphisms (SNPs) and 736 animals. BayPass software was used to analyse genotype-environment associations, resulting in the detection of 168 outlier SNPs and 232 genes within 100-kilobase windows around the outliers. The trait 'isothermality' (ratio of daily to annual temperature variation) showed the greatest number of genomic associations. Moreover, genomic regions mapping to chromosome 1 and chromosome 14 showed the most extreme Bayes Factors. Gene Ontology enrichment analysis revealed contextually relevant pathways associated with immune response, system development (progression of an organismal system over time) and keratin filament. Key genes found in candidate genomic regions identified by these analyses included STAT1, COL11A1 and COL6A3, which have been previously associated with thermoregulation, hair follicle development, lipid metabolism and high-altitude adaptation, suggesting possible roles in environmental adaptation.