Studying the association of polymorphic variants of LEP, TG5, CSN3, LGB genes with signs of dairy productivity of cattle

The efficiency of selection and breeding work in animal husbandry depends largely on the accuracy of the evaluation of the breeding value of animals. The integration of molecular genetics into applied science made it possible to assess the genetic potential of animal productivity not only on the basis of phenotype data but also directly at the DNA level. The study was conducted on the basis of Tatar Scientific Research Institute of Agriculture, FRC Kazan Scientific Center, Russian Academy of Sciences. The object of the study was DNA samples obtained from the blood of Holstein cows belonging to the stud farm “named after Lenin” of Atninsky district of the Republic of Tatarstan. Animal blood was taken from the tail vein using vacutainer tubes with 100mM EDTA. DNA was isolated from the blood in the amount of 100 µl using a set of reagents for DNA extraction from the “Ampliprime DNA-sorb-B” clinical material (NextBio, Russia), according to the method presented by the producer. DNA fragment amplification was performed in T100 Thermal Cycler (Bio-Rad, USA) and on MyCycler programmable Thermal Cycler (Bio-Rad, USA). After amplification, each DNA fragment obtained by us in the study of TG5, CSN3, LGB genes, was subjected to cleavage by a restriction endonuclease. Hydrolysis was conducted at 37°C for 12 hours. The analysis of polymorphism of candidate genes of dairy productivity of leptin, thyroglobulin, kappa casein and beta-lactoglobulin with the use of PCR-RFLP was carried out. The most common were homozygous TG5CC, CSN3AA and heterozygous LEPCT, LGBAB genotypes. The study of the effect of polymorphism of these genes on milk production showed that animal carriers of LEPCT, TG5TT, CSN3AB, LGBBB genotypes have the best indicators of dairy productivity.