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Large-Scale Genomics Reveals Three-Source Ancestry and Layered Adaptation to High Altitude in Tibetan Chickens
Zongyi Zhao1,2, Ruixue Nie3, Hailu Fan1,2
1Frontiers Science Center for Molecular Design Breeding (MOE), China Agricultural University, Beijing, China.
Summary
Tibetan chicken high-altitude adaptation results from multiple ancestral sources. These contributions, layered over time, brought distinct genetic pathways for survival on the Tibetan Plateau.
Area of Science:
- Genomics
- Animal Genetics
- Evolutionary Biology
Background:
- Tibetan chickens possess unique traits for high-altitude survival.
- The specific ancestral origins and genetic contributions to this adaptation are not fully understood.
Purpose of the Study:
- To investigate the distinct ancestral sources, their timing, and functional impacts on Tibetan chicken adaptation.
- To understand the genetic architecture of high-altitude adaptation in this population.
Main Methods:
- Admixture modeling and ancestry tract-length dating were applied to 1054 whole chicken genomes.
- Selection scans were performed using a demographic null model to identify adaptive genes.
Main Results:
- Three ancestral sources were identified: Northwest China (NWC), Sichuan-Yunnan adjacent region (SYA), and Southern Himalayan Foothills (SHF).
- Contributions were temporally stratified, with NWC being the oldest, followed by SHF, and a recent major expansion from SYA.
- Each ancestral source was linked to distinct functional categories: NWC (vascular homeostasis), SYA (metabolic regulation), and SHF (pulmonary vascular remodeling).
Conclusions:
- High-altitude adaptation in Tibetan chickens is shaped by temporally layered contributions from multiple ancestral populations.
- Distinct functional pathways were inherited from each source, highlighting a complex genetic basis for adaptation.
- Human-mediated dispersal likely played a role in shaping the genetic makeup of these highland chicken populations.
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