Goat : mRNA expression, InDel and CNV detection, and their associations with litter size.

The sorting nexin 29 () gene, a member of the SNX family, is associated with material transport and lipid metabolism. Previous studies have shown that lipid metabolism affects reproductive function in animals. Thus, we hypothesized there is a correlation between the gene and reproductive trait. To date, studies on the relationship between the gene and reproductive traits are limited. Therefore, the purpose of this study was to examine the polymorphism in the gene and its correlation with litter size. Herein, the mRNA expression levels of were assayed in various goat tissue. Surprisingly, we found that was highly expressed in the corpus luteum, large and small follicles. This result led us to suggest that the gene has a critical role in reproduction. We further detected potential polymorphisms in Shaanbei white cashmere (SBWC) goats, including insertion/deletion (InDel, = 2,057) and copy number variation (CNV, = 1,402), which were related to fertility. The 17 bp deletion (n = 1004) and the 20 bp deletion ( = 1,053) within the gene were discovered to be significantly associated with litter size ( < 0.05), and individuals the ID genotype of P1-Del-17 bp and the DD genotype of P2-Del-20bp had larger litter size. Additionally, the four CNV loci had significant correlations with litter size ( < 0.01) in our detected population. In CNV5, individuals with the median genotype were superior compared to those with loss or gain genotype in term of litter size, and in other three CNVs showed better reproductive trait in the gain genotype. Briefly, these findings suggest that could be used as a candidate gene for litter size in goat breeding through marker-assisted selection (MAS).