Analysis of bovine pituitary specific transcription factor-HinfI gene polymorphism in Indian zebuine cattle

The pituitary specific transcription factor (Pit-1) controls the expression of prolactin, thyrotropin, and growth hormone genes and is considered as an important candidate gene for several quantitative traits. The study was aimed to reveal the distribution pattern of known variants at Pit-1/HinfI locus in 16 distinct Indian native cattle (Bos indicus) breeds. PCR-RFLP analysis of 1350 bp fragment revealed the predominance of BB genotype and B allele with a mean frequency of 0.881 and 0.937, respectively, irrespective of utility type (dairy, dual, draft), geographical region (northern, central and southern) and coat colour (red/brown and grey/white). AB genotype was the next most frequent with a mean frequency of 0.119. Interestingly, only a single individual out of 723 screened was observed to have AA genotype. The significantly low frequency of A allele observed in present study differs from Bos taurine breeds. Chi square test showed non-significant (P > 0.05) difference in pattern of variant distribution, regardless of the geographical location, agroclimatic regions and coat colour. However, significant differences (P < 0.05) were observed between utility type categories (dual vs draft and dairy vs draft). This study further validates the utility of PCR-RFLP as efficient means of exploring the distribution pattern of known variants at important candidate genes in Indian zebu cattle for future breeding plans.