Genetic Diversity and Population Structure Analyses of Heat Tolerance related Genes in Korean, Tropical Native and Commercial Chickens

Global warming-induced heat stress decreases productivity and reduces the survivability of poultry, causing substantial economic losses in the poultry industry. As poultry lack sweat glands, their thermoregulatory capacity is limited, making them highly vulnerable to heat stress. Although Korean native chickens (KNCs) represent an important indigenous genetic resource, research on their heat tolerance remains limited. In this study, we selected 19 heat tolerance-related candidate genes based on previous research and extracted their single nucleotide polymorphisms (SNPs) from next-generation sequencing (NGS) data obtained from 129 individuals, including KNCs, tropical native chickens, and commercial breeds. These SNPs were then used to evaluate genetic diversity and population structure. Principal component analysis (PCA) revealed a clear separation between KNCs and the other populations, indicating distinct genetic differentiation among groups. Although differentiation among KNC lines was relatively low, the overall genetic diversity of KNCs was markedly higher than that of the other populations. This pattern of separation between groups was also confirmed in the results of F_ST and phylogenetic tree analyses. Overall, our results reveal a distinct genomic profile associated with heat tolerance in KNCs, offering essential information for understanding their unique genetic characteristics compared with other chicken populations. This analysis provides a foundation for future research aimed at enhancing heat tolerance in Korean native chickens.