Polymorphism of the heat shock protein 70 gene in indigenous chickens from different agro-climatic zones in Kenya

Climate change leads to heat stress, which is one of the most challenging environmental conditions affecting poultry. Studying thermotolerance in poultry is crucial because it may identify genetic lines that can withstand heat stress. This study aimed to investigate polymorphisms in the heat shock protein 70 (HSP70) gene in indigenous chicken. In Kenya, we collected 277 blood samples from selected chicken ecotypes from Turkana, Western Highlands, Lake Victoria, and Lamu and extracted their genomic DNA. The first 360 bp region of HSP70 was amplified using conventional PCR and then sequenced using the Sanger ABI 3730 method. The detailed analysis of the HSP70 gene fragment revealed three HSP70 haplotypes (GC, AC, and AG). Phylogenetic analysis of HSP70 revealed the presence of the ancestral haplotype GC, which dominated in Turkana ecotype. High HSP70 nucleotide diversity indices were recorded in the Turkana ecotype, while low values were recorded in the Lamu ecotype. In addition, most of the HSP70 gene variations occurred within populations. Our study provides the first account of the HSP70 polymorphisms in indigenous chickens in Kenya. The results obtained should pave the way for further in-depth studies on genes involved in heat stress regulation.