Whole genome analysis of selection associated with resistance to heat stress in chickens

Following their domestication, chickens were translocated around the world to novel environments. Through a combination of natural and artificial selection, chickens adapted to these local conditions over the last few thousands of years, creating significant genetic diversity across populations worldwide. Studying this diversity in the context of local environmental conditions may offer insights into mechanisms of adaptation to environmental stressors. In this study, we analyzed genomic data from the Chicken Genomic Diversity Consortium, applying multiple statistical approaches, including fixation index (FST), nucleotide diversity (π), Tajima’s D, and runs of homozygosity (ROH), to identify selective sweeps among indigenous chickens from Afghanistan, China, Indonesia, Iran and Pakistan, compared with White Leghorn chickens. We identified sweeps in 14 genes related to heat tolerance, associated with relevant gene ontology (GO) terms and located within ROH regions. These genes, such as CDH23, NPSR1, MCU, TRPV2, TRPV1, TRPV3, ATP2B4, CALM1, CACNB2, TRAT1, BDNF, SCIN, WIPF3, PRKD1, and DNAJC10 play crucial roles in calcium signaling pathways, thermal sensation, and the plasticity of neurodevelopmental processes. These findings illustrate the significant role of selection in shaping genomic differentiation across chicken populations and provide insights into the genetic basis of adaptation to environmental stressors.