Single Nucleotide Polymorphism in KiSS1 gene and its association with semen quality in Bos taurus and Bos indicus bulls

Abstract

Selection of high fertile bulls with the help of marker assisted selection has gained importance in recent years. The low heritability of fertility traits hampers improvement of these traits by conventional selection based on phenotypic records. No information is available on the role of SNPs in KiSS1 gene in cattle on semen quality parameters in bovines. KiSS1 genes code for Kisspeptin, which are essential upstream regulators of neurons secreting gonadotropin-releasing hormone and play crucial role in reproduction.The coding regions along with exon-intron boundaries of KiSS1 gene, was characterized using PCR-SSCP method and direct sequencing. Two genotypes were observed which were represented as SSCP pattern 1 and pattern 2 and found to carry one SNPs (T153C) and one insertion of G at 291_292bp. The bulls with pattern 2 were heterozygous with respect to the transition T153C and pattern1 bulls were homozygous with TT genotype. The transition was predicted to cause amino acid change from Valine to Alanine. The frequency of bulls with pattern1 and pattern 2 were 0.67 and 0.33 in 67 Holstein Friesian bulls and 0.73 and 0.27 in 13 Khillari bulls. The association study of genotypes with semen quality parameters revealed significant association of genotypes with acrosome integrity in fresh semen (P less than 0.05) and no association with sperm concentration, volume per ejaculate, percent live sperm and Hypo Osmotic Swelling Test (HOST) with higher acrosome integrity in bulls with pattern2. Upon validation of the results in larger population and identifying the exact role of the novel SNP T153C and insertion of G at 291_292bp, they could be incorporated in selection programme for improving fertility in bulls.as markers for acrosome integrity in cattle.