Molecular genetics analysis of milk protein gene polymorphism of dairy cows and breeding bulls in Latvia

摘要

Milk protein is the most valuable component of milk from a dietary point of view. More than 95% of ruminants’ milk proteins are coded by six structural genes: two whey proteins (α – lactalbumin and β – lactoglobulin) and four caseins (αS1 – and αS2 – caseins, β – casein, κ – casein). The object of the research was the genetic polymorphisms of milk protein genes in populations of cows and breeding bulls of milk producing breeds in Latvia. The aim was to promote cow breeding in Latvia by developing and testing molecular genetics analyses for future quantity and quality analysis of the dairy cows’ population in Latvia, based on the research of genes encoding milk protein polymorphism. In methodology the molecular markers were chosen which would be suitable for characterization of polymorphism of five milk protein genes in the population of dairy cows reared in Latvia. As a genetic method chosen the Restriction Fragment Length Polymorphism (RFLP) method and most analysed alleles of milk proteins. Using data of 719 DNA samples of dairy cows, the analysis of Latvian cows’ population was carried out through six SNP of five milk protein genes: CSN1S1 c.–175A > G, CSN2 – c.4451A > C, CSN3 c.11625C > T and c.11661A > C, LAA c.15A > G and LGB c.3106T > C. The results of PCR-RFLP analysis showed, as it was expected, that all genotypes were found in the populations.