New genetic polymorphisms of KiSS-1 gene and their association with litter size in goats

In the present study, the polymorphisms of kisspeptin (KiSS-1) gene were analyzed in 652 individuals from three goat breeds: Xinong Saanen goats (SG), Guanzhong goats (GZ) and Boer goats (BG). Three alleles (T, C and G) and four genotypes (TT, TC, CC and TG) were detected in the intron 2 of KiSS-1 gene by PCR-SSCP analysis. In addition, two single nucleotide polymorphisms (SNPs) - T2643C and 8bp base deletions (2677AGTTCCCC) were identified by DNA sequencing. The SNPs loci were in Hardy-Weinberg disequilibrium in three goat breeds (P < 0.05). After comparing genotypic distribution within three goat breeds, BG had conspicuous differences from SG and GZ (P < 0.001). Association of polymorphism with litter size was done in SG and GZ breeds, which showed to be associated with litter size in both goat breeds. The SNP in goat KiSS-1 gene had significant effects on litter size (P < 0.05). Therefore, these results suggest that KiSS-1 gene is a strong candidate gene that affects litter size in goats.