Genetic polymorphism of Prolactin and Leptin gene and their association with Production and Reproduction Traits in Sahiwal cattle in India

Abstract

Prolactin (PRL) is one of the polypeptide hormones of the pituitary gland, regulates mammary newlinegrowth, lactogenesis, reproductive and immunological functions, fluid balance and cellular growth and newlinedifferentiation, while Leptin (LEP), the fat derived protein hormone regulates the feed intake, energy newlinebalance, fertility, immune functions, important role in lactogenesis and its receptors have been found to newlinebe expressed in mammary epithelial cells. In the present study, identification of PRL and LEP gene newlinepolymorphism and its association with milk production and reproduction traits was undertaken in 154 newlineSahiwal cattle maintained at NDRl, Karnal and ILFC, DUV ASU, Mathura by using PCR-RFLP newlinetechnique. The amplified fragments of the PRL-I, PRL-II, LEP-I and LEP-ll genes revealed 156, 857, newline454 and 1820 bp respectively, the amplified products were digested with Rsal, HaeIII, Hphl and newlineSau3AI restriction endonuclease enzymes respectively. The RsallPCR-RFLP assay of PRL gene newlinerevealed three types of genotypes; 156 bp fragment (BB genotype); 82 and 74 bp fragments (AA newlinegenotype) and 156, 82 and 74- bp fragments (AB genotype) with frequencies 22.58%, 60.48% and newline16.94% respectively. Allelic frequency of A and B alleles were 0.472 and 0.528, respectively. DNA newlinesequencing revealed A-+G substitution at RsaI recognition site GTAC. After l analysis the selected newlinepopulation of Sahiwal cattle was found in Hardy- Weinberg Equilibrium. In restriction digestion of newlinePRL 857 bp product with HaellI revealed only one type of genotype. This revealed no polymorphism newlinei.e. monomorphic in nature, Further the presence of the restriction site for HaeIU in PCR products newlineconfirmed by sequencing. The obtained sequence of PRLI HaeIII after aligning was revealed deletion newlineof G from HaeIII recognition site GGCe. The HphIIPCR-RFLP assay of LEP gene revealed two types newlineof genotypes; 309 and 145 bp fragments (BB genotype); 454, 309 and 145 bp fragments (AB genotype) newlinewith frequencies 70.97% and 29.03% respectively, whereas the AA genotype was not found in these newlinesamples (0.00%). T