Analysis of ESR1 Gene Polymorphism and Lambing Association between Cele Black Sheep and Hetian Sheep

Abstract Litter size is one of the most important traits of sheep. The purpose of this study is to detect the ESR1 gene in Cele Black sheep and Hetian sheep populations, so as to lay a foundation for further improving the litter size of the population and establishing a core population with high fecundity. Jugular blood DNA was extracted from healthy Cele Black sheep and Hetian sheep, and two polymorphic loci (rs399356740 and rs590747651) of ESR1 gene in two sheep breeds were genotyped by Polymerase Chain Reaction (PCR) and Sanger sequencing, and the genetic parameters and lambing number were analyzed. The results of sequencing showed that there were three genotypes of AA, AT and TT at rs399356740 and rs590747651 loci in Cele Black sheep and Hetian sheep, and all of them showed moderate polymorphism. The dominant allele of rs590747651 locus in Cele Black sheep is T and the dominant allele of rs590747651 locus in Hetian sheep is A, which may be the reason for the difference in fecundity between the two sheep populations. The mutation site of rs590747651 was in Hardy-Weinberg equilibrium in Hetian sheep population, and the results of association analysis showed that the lambing number of AA and TT type at rs590747651 locus was significantly higher than that of AT type in Hetian sheep population, and the dominant genotype was AA type, which indicated that rs590747651 mutation could be considered as a molecular assistant marker for lambing trait in Hetian sheep. However, due to the small sample size, the rs590747651 locus had nothing to do with the litter size of Cele Black sheep. This study can be used as a potential candidate genetic marker for lambing performance in sheep breeding, and provide reference data for the study of lambing performance of sheep.