Characterization of 5’ Upstream Region and Identification of Polymorphism in Intron 1 of Prolactin (PRL) Gene using HaeIII PCR-RFLP in Indian Cattle Breeds

Prolactin (PRL) gene is an important lactogenic candidate gene, plays a crucial role in mammary gland development and in the initiation, maintenance of lactation and expression of milk protein genes. In the present study, characterization of PRL 5) upstream region and investigation of status of intron 1 polymorphism was carried out in Indian cattle breeds. An 857 bp fragment of 5) upstream region of PRL gene consisting of part of promoter, exon1 and partial intron 1 was amplifed by PCR and subsequently sequenced in Indian breed of cattle. Nucleotide sequences of PRL 5) upstream region exhibited a high degree (>98%) identity among Indian as well as exotic cattle breeds. HaeIII polymorphism screening in PRL intron 1 of Indian cattle breeds including Sahiwal (n = 154) and Hariana (n = 50) revealed monomorphic pattern, only, AA genotype (deletion homozygote) was found and confrmed by sequencing. The obtained sequences of PRL after aligning was revealed absence of HaeIII recognition site GGCC due to deletion of G and consequently, we could not perform the association study of this deletion with milk production traits.