Small Ruminant Genomics and Adaptation to Climate

Understanding molecular mechanisms underlying livestock adaptation to environmental challenges is a key factor to develop a “climate-smart” agriculture, able to quickly respond to the rapid climatic changes envisaged for the next decades. Thanks to the availability of landscape genomic tools and medium-density DNA array data, we explored livestock adaptation to diverse environmental conditions, by focusing on sheep and goat populations reared in a spectrum of different regional climates worldwide. Sheep data from the International Sheep Hapmap project and goat data from the ADAPTmap initiative have been analysed with MatSAM and Samßada software, respectively. In sheep we identified 230 SNPs with evidence for climate-driven selection pressure. Gene ontology analysis of genes found within linkage distance from the selected SNPs identified 17 candidates significantly over-represented for biological processes related to energy metabolism, and endocrine and autoimmune regulation. In goats a total of 66 SNPs significantly associated with environmental variables were identified, with the highest numbers of significant associations occurring on chromosomes 5, 7, 14 and 22. Among the 27 genes found within linkage distance from these SNPs, seven were previously recorded to be involved in biological functions related to feed intake, dairy production, immune system, and wool follicle development in several livestock species. The environmental variables appearing in the most significant models were the maximum temperature in February, followed by temperature seasonality.