Genotypic profiling of coding region of leptin gene and their association studies on reproductive and milk production traits in Sahiwal and Frieswal cattle of India

Leptin gene has its role in appetite, metabolism, growth and milk production in cattle. Single nucleotide polymorphisms (SNPs) in leptin gene in different cattle breeds have been reported and subsequently associated with their production performance. The objective of this study was to evaluate the association of genetic differences in the bovine leptin gene with milk production, reproduction, milk constituents in Sahiwal and Frieswal cattle of India. In total, one hundred and seventy six cows were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to screen the presence of three SNPs in leptin gene. The testing of Hardy- Weinberg equilibrium for the three SNPs of within Frieswal and Sahiwal population indicated that the polymorphism site in the populations fitted with Hardy-Weinberg equilibrium (P > 0.05) except for C/BspEI/T and C/NruI/T position in Sahiwal. Polymorphism C/NruI/T have significant association with age at first service and age at first calving and heterozygotes have more prolonged age at fist service and age at first calving. For milk protein, C/BspEI/T and C/HphI/T was found to have significant effect. For lactose and SNF, C/HphI/T polymorphism has found to be significant. In case of combined genotyping, genotype CTCTCC (713.00±167.99 days) was found to have noticeable higher age at first service and age at first calving. But milk production higher first lactation yield was noted for T (3987.00±337.86 kg). Keywords: Leptin gene, polymorphism, Frieswal, Sahiwal, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), combined genotype. African Journal of Biotechnology Vol. 12(42), pp. 6140-6146