Polymorphism of KiSS-1 gene and its association with litter size in Mehraban sheep

Kiss1 gene is known as one of the genes affecting fertility. In the present study, DNA polymorphisms were investigated in gene 331 bp exon one and 286 bp of intron one of Kiss1 and their associations with reproduction trait (liter size) in 100 Mehraban sheep. Polymerase chain reaction based single strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods were used to identify eventual polymorphisms. The results showed single nucleotide polymorphism at three sites (g102C> T, g.155G> C and g.272G> A) with four different band patterns (four haplogenotypes) in exon one. All samples were detected with the same SSCP banding patterns and no polymorphism in intron one. The Chi-square test was used to compare the observed and expected genotypic frequencies. It was shown that the frequency of genotypes were significantly different in g.102C> T and g.272G> A mutations in exon one and they weren’t in the Hardy-Weinberg equilibrium (P˂ 0.01). In the association analysis, the identified haplogenotypes were significantly associated with litter size, the number of lambs per parturition (P< 0.05). The results of this study showed that the variation in exon one of the Kiss1 gene can be considered in marker assistance selection programs in Mehraban sheep breed.