Geographic Distribution of a Missense Mutation in the KRT38 Gene and Its Association with Heat Tolerance in Chinese Indigenous Cattle Breeds

Context China has a vast area across many temperature zones and a variety of cattle breeds. These cattle resources are ideal models to research their adaptability to the environment. The KRT38 gene is an acidic protein, and its coding product can be used as a component of hair production. Aims The objective of this study was to investigate the diversity of the KRT38 gene in Chinese local cattle and the association of different genotypes with mean temperature (T), relative humidity (RH) and temperature humidity index (THI). Methods A missense mutation g.41650738 A > G in the KRT38 gene was screened from the database of bovine genomic variation (BGVD), was genotyped in a total of 246 samples from 15 local cattle breeds in China by PCR amplification and sequencing. Finally, the correlation between the locus and the three climatic factors was analysed. Key results We successfully obtained the frequency of this SNP in three groups of cattle in northern, central and southern China. The frequency of allele A gradually declined from north to south, while the frequency of allele G showed the opposite trend with a clear geographic distribution. Conclusions Our results indicate that KRT38 variation in Chinese indigenous cattle might be linked to heat tolerance. Implications Our analysis may support in finding out its importance as a genetic signal for heat tolerance in cattle reproduction and genetics. ### Competing Interest Statement The authors have declared no competing interest.