Evaluation of CYP19 as a candidate gene for milk production traits in native cattle and buffalo populations of Southern India

Candidate gene approach facilitates searching causative polymorphisms that influence quantitative traits. Biosynthesis of estrogen catalyzed by aromatase, a product of the CYP19 gene affect lactogenesis. The objective of the study was to determine the polymorphism in the promoter region of CYP19 gene by PCR-RFLP and was undertaken on 502 bovine species belonging to Ongole (Bos indicus), Holstein Friesian crossbred, Jersey crossbred cattle, and Murrah buffaloes reared across Southern India. The frequency of the CYP19A allele was 0.90, 0.88, and 0.77 in Jersey crossbred, HF crossbred, and Ongole cattle, respectively. The BB genotypes could not be observed in Jersey crossbred cattle. Fixation of the B allele was evident in Murrah buffaloes. The Hardy-Weinberg equilibrium was verified and general linear model procedure was adopted to evaluate the effect of CYP19/PvuII genotype on milk production traits. The AA genotypes (2111.53 +/- 51.84 kg) in Jersey crossbred cattle, AB genotypes (2529.00 +/- 238.08 kg) in Holstein Friesian crossbred and BB genotype (590.85 +/- 92.29 kg) in Ongole cattle yielded more milk. The fat content of milk in AB genotypes was higher in all the cattle. The solid-not-fat and lactose content was more in the milk of BB genotypes and protein in AB genotypes of Ongole cattle. The fat, SNF, protein, and lactose content in Murrah buffalo milk was 7.26 +/- 0.62%, 9.20 +/- 0.19%, 3.44 +/- 0.06%, 4.87 +/- 0.11%, respectively. No significant (p > 0.05) effect of CYP19/PvuII genotypes on milk production and composition was found in any of the genetic groups studied. The sequence analysis of CYP19 P 1.1 revealed additional SNPs in all the cattle under study. A novel SNP at 82 nucleotides upstream of the PvuII restriction site was observed in Murrah buffaloes.