Association of Polymorphisms in Candidate Genes with the Litter Size in Two Sheep Breeds

摘要

Increasing litter size is critical for the intensive sheep production system. Genetic marker-assisted selection (MAS) based on proven molecular indicators could enhance the efficacy of sheep selection with improving litter size traits. Many single nucleotide polymorphisms (SNPs) linked with litter size in Hu sheep and Small-tailed Han sheep have been identified. However, they usually explain a small portion of genetic variation and additional genetic markers linked with litter size have not been found. The present study investigated the potential SNPs in ten genes as candidate markers for improved litter size in sheep. As a result, nine SNPs in six out of ten genes can be served as useful genetic markers to improve the selection of litter size since they are significantly associated with litter size either in Hu sheep or Small-tailed Han sheep. Further, a combined haplotypes analysis of the two loci ( : g.35862868C>T and : g.35862947G>T) revealed that H2H3 (CTTT) combined haplotypes had the largest litter size than the rest combined haplotypes and more than those with either mutation alone in Small-tailed Han sheep. Our knowledge is essential to implement the MAS in sheep and further to increase the profitability in the sheep industry.