POLYMORPHISM AND ALLELIC FREQUENCY OF CSN2 IN DIFFERENT CATTLE BREEDS IN BULGARIA

D. Yordanova, T. Angelova, J. Krastanov, G. Kalaydhziev, V. Karabashev, S. Laleva, N. Oblakov, M. Cassandro

Abstract: Several scientific researches for the definition of the polymorphism of the beta casein (CSN2) – one of the main milk proteins, prove the presence of 13 variants. The authors indicate that the presence of this gene reduces the serum cholesterol and the concentration of lipids, which has an important role in the prevention of cardiovascular diseases. (Kaminski et al., 2007). The target of the present research is to determine the polymorphism of milk proteins of CSN2 for different cattle breeds, raised in Bulgaria. A total of 427 tissue samples were analyzed from cows of different breeds – Bulgarian brown cattle, Bulgarian black-multicoloured cattle, Short-horn Rhodope cattle and Iskar cattle. The allelic and gene frequency of milk proteins have been defined through PCR-RFLP analysis in the laboratory of the University of Padua, Italy. Two allelic frequencies are determined – A и B, of CSN2; for all frequencies the object of analysis – allele A, is characterized by bigger frequency, compared to allele B. Three genotypes of CSN2 have been defined – AA, AB и BB. The homozygous genotype AA differs from the other two found by us genotypes, having the highest percentage.
For the commercial breeds, which are subject to this analysis, has been determined a presence of homozygous ВВ genotype.

Keywords: allelic frequency; CSN2; milk protein; polymorphism

Date published: 2018-03-14