Xiwen Guan

Over the years, indigenous cattle have not only played an essential role in securing primary food sources but have also been utilized for labor by humans, making them invaluable genetic resources. The Zhaotong cattle, a native Chinese breed from the Yunnan province, possess excellent meat quality and resistance to heat and humidity. Here we used whole genome sequencing data of 104 animals to delve into the population structure, genomic diversity and potential positive selection signals in Zhaotong cattle. The findings of this study demonstrate that the genetic composition of Zhaotong cattle was primarily derived from Chinese indicine cattle and East Asian cattle. The nucleotide diversity of Zhaotong cattle was only lower than that of Chinese indicine cattle, which was much higher than that of other taurine cattle. Genome-wide selection scans detected a series of positive candidate regions containing multiple key genes related to bone development and metabolism (CA10, GABRG3, GLDN and NOTUM), meat quality traits (ALG8, LINGO2, MYO5B, PRKG1 and GABRB1), immune response (ADA2, BMF, LEF1 and PAK6) and heat resistance (EIF2AK4 and LEF1). In summary, this study supplies essential genetic insights into the genome diversity within Zhaotong cattle and provides a foundational framework for comprehending the genetic basis of indigenous cattle breeds.

Dabieshan cattle are a typical breed of southern Chinese cattle that have the characteristics of muscularity, excellent meat quality and tolerance to temperature and humidity. Based on 148 whole-genome data, our analysis disclosed the ancestry components of Dabieshan cattle with Chinese indicine (0.857) and East Asian taurine (0.139). The Dabieshan genome demonstrated a higher genomic diversity compared with the other eight populations, supported by the observed nucleotide diversity, linkage disequilibrium decay and runs of homozygosity. The candidate genes were detected by a selective sweep, which might relate to the fertility (GPX5, GPX6), feed efficiency (SLC2A5), immune response (IGLL1, BOLA-DQA2, BOLA-DQB), heat resistance (DnaJC1, DnaJC13, HSPA4), fat deposition (MLLT10) and the coat color (ASIP). We also identified the “East Asian taurine-like” segments in Dabieshan cattle, which might contribute to meat quality traits. The results revealed by the unique and valuable genomic data can build a foundation for the genetic improvement and conservation of genetic resources for indigenous cattle breeds.

The heat shock factor 1 (HSF1) gene is a regulator of the heat stress response, maximizing HSP protein expression survival. In this research, we explored the frequency distribution of a missense mutation (NC_037341.1 g.616087A > G, rs135258919) in the HSF1 gene in Chinese cattle with amino acid substitution, valine to alanine. This mutation could be related to the heat tolerance in Bos indicus. A total of 941 individuals representing 35 Chinese native cattle breeds, combining pure taurine (Angus) and indicine cattle, were used to determine the genotypes of the mutation through PCR and partial DNA sequencing. The results showed significant differences in allele frequencies and their genotypes amongst Chinese cattle from different regions. Allele G or indicine-specific allele frequency diminished from south to north China, while allele A (genotype AA) or the taurine-specific allele had a contrary pattern, which agreed with the distribution of taurine and indicine cattle. According to the association analysis, the NC_037341.1 g.616087A > G (rs135258919) of the bovine HSF1 gene, annual temperature (T), relative humidity (RH), and the temperature humidity index (THI) (p < 0.01) were interrelated closely, which indicated that the NC_037341.1 g.616087A > G of the HSF1 gene is associated with heat tolerance in indicine cattle.