Genomic Analyses for Selective Signatures and Genes Involved in Hot Adaptation Among Indigenous Chickens From...

Area of Science:

• Animal Genomics
• Climate Change Adaptation
• Poultry Science

Background:

• Climate change and extreme weather pose significant challenges to global livestock production.
• Indigenous livestock possess valuable genetic resources for understanding climate resilience.
• Breeding for enhanced climate adaptability is crucial for sustainable livestock systems.

Purpose of the Study:

• To identify selection signatures and genes associated with hot adaptation in indigenous tropical chickens.
• To investigate the genetic mechanisms underlying heat tolerance in diverse chicken populations.
• To provide insights for poultry breeding programs focused on climate resilience.

Main Methods:

• Genomic analysis of 65 indigenous chickens from different tropical climates.
• Utilized cross-population extended haplotype homozygosity (XP-EHH) to detect positively selected genes (PSGs).
• Validated PSGs using multiple methods including composite likelihood ratio, genetic differentiation, nucleotide diversity, Tajima's D, and decorrelated composite of multiple signals.

Main Results:

• Identified unique PSGs in each local chicken group related to thermoregulation and hot adaptation (nerve, vascular, immune functions, metabolism, kidney).
• Observed parallel evolution of hot adaptability, with different genetic pathways and gene sets across tropical regions.
• A single common PSG across all groups was detected by XP-EHH but not consistently validated by other methods.

Conclusions:

• Indigenous chickens exhibit parallel evolutionary strategies for hot adaptation, utilizing distinct genetic mechanisms.
• The identified genes offer valuable insights into the genetic basis of heat tolerance in poultry.
• Findings support practical applications in breeding programs for developing climate-resilient chicken breeds.