The use of different methods to research the effect of K232A polymorphism of the DGAT1 gene on dairy productivity of cows

Abstract

Today, the study of genes-markers of quantitative traits is an urgent task. According to numerous scientific works, it is known that the K232A mutation in the DGAT1 gene is associated with signs of milk production in cattle: aalele K with a% fat content in milk, and allele A with the amount of milk. In this regard, the development of an optimal method for detecting SNP and allelic polymorphism is of scientific interest. To study the K232A polymorphism, two methods of molecular genetic analysis were used in this work: 1) real-time PCR with a system of primers and probes labeled with FAM and R6G fluorochromes; 2) PCR-RFLP with processing of amplification products with restriction endonuclease BglI and detection of samples in 15% polyacrylamide gel using a gel documentation system. The study was carried out in two stages, corresponding to two reporting periods on the farm. At the first stage, 200 cows were genotyped using real-time PCR.All animals turned out to be homozygous for allele A. At the second stage, the method of PCR polymorphism of the lengths of restriction fragments was used, with the help of which the genotypes of 102 animals were established - 64 cows with the AA genotype; 34 heads with the AK genotype and 4 heads with the KK genotype. The frequency distribution corresponded to the Hardy-Weinberg equilibrium. Allele frequencies were A - p = 0.79; K- q = 0.21. Chisquared value х2=0,04(р<0,05). Cows with the AA genotype had significantly high milk yield rates of +341.8 kg, p<0.01; with AK genotype, fat percentage +0.131, p<0.01 in 305 days 1 lactation.Calculation of the Student's criterion when comparing milk yield and fat content for full lactation (№1) of cows with different genotypes showed that all the empirical values of are in the zone of insignificance.