Determination of genetic structure in terms of kappa casein (CSN3), β-lactoglobulin (LGB), prolactin (PRL) and DGAT1 (diacylglycerol acyltransferase1) gene locus and the relationship between these characteristics and milk yields of holstein cows

The aim of this study was to identify the genetic diversity of κ-casein, β-lactoglobulin, prolactin and DGAT1 genes and the possible associations between these polymorphisms with milk yields in a total of 517 Holstein cows registered to Cattle Breeders' Association of Turkey in Antalya province. In order to determine the κ-casein-HinfI, β-lactoglobulin-HaeIII, prolactin-RsaI and DGATI-CfrI polymorphisms, PCR-RFLP method was used. In this study, two types of alleles A and B for κ-casein, β-lactoglobulin, prolactin and K and A for DGATI loci, were identified. The frequencies of A and B alleles were calculated as 0.8279 and 0.1721 for κ-casein, 0.4662 and 0.5338 for β-lactoglobulin, 0.8762 and 0.1238 for prolactin loci, respectively. Allele frequencies of DGAT1 locus were found as 0.6441 for K allele and 0.3559 for A allele. The analyzed population is in Hardy-Weinberg equilibrium for all loci. In addition, there were no statistically significant relationships between the genotypes of κ-casein-HinfI, β-lactoglobulin-HaeIII and DGAT1-CfrI polymorphism and milk yield whereas a significant association between identified prolactin-RsaI polymorphism and milk yield was found (P<0.05).