Yakut cattle breed milk and blood proteins polimorphism

The aim of research is to study the polymorphic systems of milk and blood proteins of subpopulations of the Yakut cattle breed in order to create a more complete picture of the genetic situation in the population, covering four loci. Research objectives are determination of the frequency of occurrence of alleles and genotypes at the loci of beta and kappa casein, whey proteins - beta-lactoglobulin and alpha-lactalbumin. The study was carried out by the method of vertical electrophoresis on polyacrylamide gel, using the method of salt extraction of DNA and polymerase chain reaction (PCR). Three alleles A, B and C were identified at the -Cn locus. It should be noted that alleles A and B are also often found in Yakut cattle. Thus, 71 % of this livestock was homozygous for allele A, i.e., had -Cn AA genotype. The frequency of occurrence of heterozygous individuals was 29 %, of which individuals with a combination of B and C alleles were most common. No alleles B and C were found in the homozygous state and animals with the -Cn AC genotype, i.e., a heterozygous AC combination. The degree of realization of possible genetic variability for this locus was 43.7 %, which is a satisfactory indicator. There is also a shortage of heterozygous individuals. From the presented data on the study of milk protein polymorphism (-Cn, k -Cn, -Lg, -La) and the results of PCR analysis of blood samples at the k-Cn locus, the S1-Cn locus turned out to be monomorphic. A gene imbalance is noted at the -Cn and k-Cn loci. In the -La and -Lg, the gene balance is not disturbed, but a very low level of realization of possible variability is noted. In our opinion, the disturbance of the gene balance at the loci is a consequence of the random drift of genes due to the small number and isolation of the livestock.