Sheep have been well adapted to thrive in a diverse range of climates during the domestication andbreed development process.These climate-mediated selective pressures have shown to influence variation inphenotypes such as body size and wool type within and among breeds and, meanwhile,left genetic "footprints" intheir genome.With the advent of a dense setof genome-wide SNPs, we can search for signatures of naturalselection across the sheep genome driven by such climate forces.From the International Sheep HapMap Project(including 74 worldwide sheep breeds),genome-wide data of ca.SOK SNPs in a diverse collection of 32 old nativebreeds,which have been under different local climates,were selected for the analyses.We first performed a varietyof selection tests to detect signals of selection,usingapproaches based on genetic data alone or the correlationbetween allele frequencies and climate variables,in 11 highly genetically differentiated populations withcontrasting climates.We demonstrated strong evidence for selective pressures acting on DYPR,RAB3GAP1 andGRIN2B,three candidate genes implicated in common metabolic and neuromodulation processes.We furtherlocalized the signals of selection particular regions of the genes.Our results imply that adaptations to variousclimates shaped the spatial distribution of particular variants and such loci should be a particular source accountingfor significant phenotypic variation.Further molecular and functional analyses of these candidate genes arenecessaryto elucidate the genetic architecture of climate-mediated adaptive traits in sheep.
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