Analysis of Migration and Adaptive Evolution in Tibetan Sheep Populations

Area of Science:

• Genomics
• Animal Genetics
• Evolutionary Biology

Background:

• The genetic basis of Tibetan sheep adaptation to high-altitude environments is not well understood.
• Tibetan sheep inhabit diverse high-altitude regions on the Qinghai-Tibet Plateau.

Purpose of the Study:

• To investigate the population genomics of Tibetan sheep.
• To identify genes and pathways involved in adaptation to high-altitude environments.

Main Methods:

• Whole-genome resequencing of 80 Tibetan sheep individuals.
• Population-level genomic selection signal analysis using single-nucleotide polymorphisms (SNPs).
• Comparative genomic analysis across different environmental conditions.

Main Results:

• Tibetan sheep originated in northern China with South Asian gene flow.
• Identified five key genes (HIF1AN, HBE1, HBE2, TNFAIP3, RAD50) under positive selection, linked to hypoxia and UV radiation adaptation.
• Discovered candidate genes (TP53, ATG101, ATP12A, KRT80, KRT7) for energy/water homeostasis and hair development in cold, arid environments.
• Observed stronger selection for energy and water homeostasis in high-altitude arid deserts, with HIF-1 pathway mitigating oxidative stress.

Conclusions:

• Tibetan sheep exhibit distinct genomic adaptations to varied high-altitude environments.
• The findings support a northern China origin and highlight specific genetic mechanisms for survival in extreme conditions.
• Genomic insights provide a foundation for understanding and conserving adaptive traits in Tibetan sheep populations.