Analysis of genetic diversity and genetic structure of Qinchuan cattle conservation population using whole-genome resequencing.

In the conservation of livestock and poultry resources, population genetic diversity and genetic structure of the conservation population are important factors affecting the effectiveness of conservation. In this study, whole-genome resequencing technology was used to detect genomic variation in 100 Qinchuan cattle (30 bulls and 70 cows). By analyzing population genetic diversity, runs of homozygosity (ROH) distribution features, kinship relationships, and family structure, the conservation effectiveness of Qinchuan cattle was comprehensively evaluated. The results showed that a total of 20,968,017 high-quality SNPs were detected in 100 Qinchuan cattle, the average minimum allele frequency was 0.191±0.124, the average polymorphic information content was 0.279±0.131, and the average observed heterozygosity was 0.275±0.131, the average expected heterozygosity is 0.279±0.131, indicating that the genetic diversity of the Qinchuan cattle conservation population is relatively rich. The average identity by state (IBS) distance of the Qinchuan conservation population was 0.243±0.020, with a value of 0.242±0.021 for the bulls. The results of the kinship G-matrix were consistent with the results of the IBS distance matrix, both showing that some individuals in the conservation population had close kinship. A total of 8258 genomic ROH were detected in 100 Qinchuan cattle, with a total length of 9.64 GB. The average length of ROH fragments was 1.167±1.203 Mb, 69.35% of the ROH were short ROH with a length of 0.5~1 Mb, and the average total length of ROH per individual was 96.40 Mb. The average inbreeding coefficient based on ROH was 0.039±0.039, with a value of 0.044±0.035 for the bulls, indicating that some bulls had a certain degree of inbreeding accumulation. The results of the phylogenetic tree combined with kinship analysis showed that the individuals in the Qinchuan cattle conservation population could be divided into eight families, including seven families with bulls and one family without bulls. This study demonstrated that the genetic diversity of the Qinchuan conservation population is relatively rich, with no significant inbreeding accumulation, but there is a risk of inbreeding among some individuals. Therefore, it is necessary to strengthen selection and mating to ensure the sustainable development of Qinchuan cattle resources.

Novel SNPs of the caprine growth hormone secretagogue receptor (GHSR) gene and their association with growth traits in goats.

Growth hormone secretagogue receptor (GHSR), a G protein-coupled receptor that binds ghrelin, plays an important role in the central regulation of pituitary growth hormone secretion, food intake, and energy homeostasis. This study analyzed polymorphism of the caprine GHSR gene as a genetic marker candidate for growth traits in goats. Two single nucleotide polymorphisms (GU014697:g.165G-->A and GU014697:g.548T-->C) were identified in exon 2 of the caprine GHSR gene by PCR-single-strand conformation polymorphism and DNA sequencing methods. Their associations with growth traits were analyzed in 313 Xuhuai goats. The results indicated that GU014697:g.548T-->C had significant effects on growth traits. Body length and body length index were significantly higher in individuals with genotype TT than CC and CT in (P < 0.05). TT individuals also tended to have better performance in other traits, such as body height and chest circumference, although there were no statistical differences (P > 0.05). This suggests that GHSR is a strong candidate gene that affects growth traits in goats.