Disease & heat resistance

Genetic mechanisms underlying climate resilience in Spanish sheep: Adaptation to heat and water stress

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Abstract

Sheep production in semi-arid regions is increasingly threatened by climate change, as increasing temperatures and decreasing water availability challenge livestock productivity and welfare. Understanding the genetic mechanisms that regulate adaptation to these combined stressors is essential for maintaining sustainable production. In this study, we have investigated the statistical association between the genetic variation of 22 autochthonous sheep breeds from Spain, a European hotspot for severe droughts and increasing temperatures, and a set of focal environmental variables to identify genes and biological pathways putatively involved to local adaptation to varying degrees of heat and water stress. For this purpose, 1142 ewes were genotyped for 54,000 single nucleotide polymorphisms (SNPs) using the Illumina Ovine SNP50 BeadChip. Environmental variables related to heat stress (temperature-humidity index), water availability (Thornthwaite aridity index, Emberger's pluviothermic quotient, global aridity index, topographic wetness index, precipitation of driest month, precipitation seasonality, precipitation of coldest quarter, precipitation of driest quarter and precipitation of warmest quarter) and temperature (maximum temperature of warmest month, mean temperature of wettest quarter, mean temperature of driest quarter and mean temperature of warmest quarter) were characterised at each sampling site. To control for population structure, we studied the ancestral origin of each breed via a sparse non-negative matrix factorization (sNMF) approach. Gene-environment associations (GEAs) were detected through latent factor mixed models (LFMMs) and partial redundancy analysis (pRDA), and significant SNPs were annotated using the Ensembl database (Rambouillet 2.0). Our analysis revealed moderate population structure, with pairwise FSTs ranging from 0.03 to 0.14, and identified 16 ancestral populations. This finding is consistent with a complex demographic history involving extensive admixture. We found 11 and 84 SNPs significantly associated with environmental variables (FDR < 0.05) using LFMMs and pRDA, respectively, with most of them highly correlating with the mean temperature in the wettest quarter (48.4%) and with the summer temperature-humidity index (23.2%). We identified 83 genes in linkage disequilibrium (r< 0.2) with the candidate SNPs and involved in various processes, including molecular functions (chromatin regulation, kinase activity and G protein-coupled receptor signalling) as well as cellular and organismal processes (cytoskeleton dynamics, vesicle transport, cell growth and development of bone, cartilage and neural tissues). These genes play central roles in cellular communication, morphogenesis, and tissue specialisation. Our results provide insight into the genetic basis of sheep's adaptation to water and heat stress, supporting the use of genome-informed breeding to improve resilience in changing environments, such as semi-arid regions.

Keywords: 2026

How to Cite:

Adán, S., Amills, M., Arranz, J., Bermejo, L., Bravo, J., Calvete, C., Calvo, J., Casellas, J., Domingo, A., Fernández, A., Gracia, A., Jordana, J., Joy, M., Lobón, S., Martà­nez, A., Pérez-Redondo, S., Pons, à., Ramón, M., Serrano, M., Ugarte, E. & Vajana, E., (2026) “Genetic mechanisms underlying climate resilience in Spanish sheep: Adaptation to heat and water stress”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2281205. doi: https://doi.org/10.31274/wcgalp.23455

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