Genomic Landscape of Copy Number Variations and Their Associations with Climatic Variables in the World's Sheep

Area of Science:

• Genomics
• Animal Genetics
• Evolutionary Biology

Background:

• Sheep exhibit significant phenotypic diversity and adaptation to varied climates.
• Copy number variations (CNVs) are known to influence adaptive evolution in domestic animals.
• Previous research suggests CNVs play a role in climate adaptation.

Purpose of the Study:

• To identify environment-driven copy number variations (CNVs) in sheep.
• To investigate the association between CNVs and climatic variables.
• To understand the genetic basis of climate adaptation in sheep populations.

Main Methods:

• Constructed a genomic landscape of 39,145 CNVs across 47 sheep populations using high-density SNPs.
• Applied a multivariate regression model to detect environment-driven CNV signatures.
• Performed enrichment analysis of gene sets within CNVs and overlapped CNVs with known sheep quantitative trait loci (QTLs).

Main Results:

• Identified 136 deletions and 52 duplications significantly associated with climatic variables (P_adj. < 0.05).
• Found climate-mediated selective CNVs linked to genes involved in heat/cold adaptation, wool traits, DNA repair, metabolism, reproduction, growth, and immunity.
• Observed significant associations between CNVs and solar radiation, with enriched gene ontology terms related to nucleotide and GTPase activity.

Conclusions:

• Copy number variations (CNVs) are significant genomic markers for sheep adaptation to specific climatic conditions.
• CNVs provide insights into the genetic mechanisms underlying adaptation to environmental factors like temperature and solar radiation.
• These findings can inform selective breeding strategies for developing climate-resilient sheep breeds.