Association analysis of polymorphisms in , , , and genes with reproductive traits in different sheep breeds.

The aim was to investigate the relationship between polymorphisms of gene mutation loci and reproductive traits in local sheep breeds (Duolang Sheep) and introduced sheep breeds (Suffolk, Hu Sheep) in Xinjiang to provide new molecular markers for the selection and breeding of high fecundity sheep. The expression pattern of typing successful genes in sheep tissues was investigated by RT-qPCR technology, providing primary data for subsequent verification of gene function. The 26 mutation loci of , , , , and genes were typed using KASP. Association analyses were performed using SPSS 25.0, and the typing results showed that five genes with six loci, (g.14962207 C>T), (g.48271079 C>A), (g.27107842 T>C, g.27108855 G>A), (g.86134602 G>A), and (g.80789180 T>G) were successfully typed. The results of the association analyses showed that (g.14962207 C>T), (g.27108855 G>A), (g.48271079 C>A), and (g.80789180 T>G) caused significant or extremely significant effects on the litter size in Duolang, Suffolk and Hu Sheep populations. The expression distribution pattern of the five genes in 12 sheep reproduction-related tissues was examined by RT-qPCR. The results showed that the expression of the gene in the uterus, the gene in the ovary, and the gene in hypothalamic-pituitary-gonadal axis-related tissues were significantly higher than in the tissues of other parts of the sheep. and genes were highly expressed both in reproductive organs and visceral tissues. In summary, the (g.14962207 C>T), (g.27108855 G>A), (g.48271079 C>A), and (g.80789180 T>G) loci can be used as potential molecular markers for detecting differences in reproductive performance in sheep. Due to variations in typing results, the (g.27107842 T>C) and (g.86134602 G>A) loci need further validation.