Analysis of Genetic Variation at the Prolactin-RsaI (PRL-RsaI) Locus in Indian Native Cattle Breeds (Bos indicus)

Abstract

This study assessed the distribution pattern of allelic variants at the prolactin-RsaI locus in 23 Indian native cattle breeds (Bos indicus). PCR-RFLP genotyping of a 156 bp fragment of prolactin (PRL) in exon 3 revealed the predominance of the heterozygous AB genotype (mean frequency 0.58) irrespective of utility type (dairy, dual, draft), geographic region (northern, central, southern), and coat color (red, gray) of the breeds analyzed. The overall frequencies of homozygous AA (0.22) and BB (0.20) genotypes were in a similar range. The PRL (A) and PRL (B) alleles exhibited similar gene frequencies (means 0.52 and 0.48, respectively). The existing profile of the PRL-RsaI gene locus in a large set of Indian native cattle breeds was different from that of Bos taurus and cattle breeds of other countries, where either the BB genotype and PRL (B) allele or the AA genotype and PRL (A) allele have been reported to be more prevalent.

Türkiye’deki Holştayn, İsviçre Esmeri ve Simmental Sığır Irklarında Kapa-Kazein, Büyüme Hormonu ve Prolaktin Genlerinin Allel Frekansları

“…The bovine PRL locus is reported to have two alleles, namely, the A and B alleles 8 . Previous research has shown that in HL cattle raised in Russia, South Korea 15 and Lithuania 21 the frequency of the PRL-A allele is higher than that of the B allele.…”

“…It has been reported that, in cattle, the bGH gene is correlated with certain yield traits, in particular with milk yield and quality, growth 6 , carcass composition and quality 7 . In this context, it is considered that it could be of use as a candidate gene in animal improvement programmes targeted at increasing milk and meat yields 8 . Previous molecular genetic studies have demonstrated that yield traits such as milk yield and body weight gain are correlated with certain polymorphisms of the bGH gene 6 .…”

“…In mammals, prolactin is responsible for the onset and maintenance of lactation, the growth of the mammary glands, and lactogenesis 8 . In view of the effects described above, it is considered that this gene could be used as a potential genetic marker of milk yield in cattle 8 .…”

“…In view of the effects described above, it is considered that this gene could be used as a potential genetic marker of milk yield in cattle 8 . However, information available on polymorphisms of the PRL gene in cattle remains limited.…”

“…A few polymorphisms have been reported for the bovine PRL gene 9 . Literature reports are available, which report correlation to both exist 8 and not exist 10 between PRL-RsaI polymorphisms and several traits, including milk yield, milk fat rate and milk protein content in the particular animal species and breeds investigated. For, it is considered that the variants of this gene could be used in the development of an appropriate test method for genetic improvement programmes and animal breeding 10 .…”