Genomic Analyses Reveal Genetic Adaptations to Tropical Climates in Chickens

The genetic footprints of adaptations to naturally occurring tropical stress along with domestication are poorly reported in chickens. Here, by conducting population genomic analyses of 67 chickens inhabiting distinct climates, we found signals of gene flow from Tibetan chickens to Sri Lanka and Saudi Arabia breeds, and identified nine genes related to heat stress both in tropical desert and tropical monsoon island climates. Notably, in tropical desert climate, advantageous alleles of TLR7 and ZC3HAV1 inhibited replication of viruses in cells, indicating immune adaptation to defense against zoonotic diseases. Furthermore, comparative genomic analysis showed that four genes involved in arachidonic acid metabolism (OC90, PLA2G12B, GPR17 and TNFRSF11A) had undergone convergent adaptation to the tropical desert climate between birds and mammals. Our study offers novel insights into genetic mechanisms of adaptations to tropical climates in birds and other animals, and provides practical value for breeding design and medical research on avian viruses.