GENETIC VARIANTS FROM THE SIX LOCI CODING THE MAJOR MILK PROTEINS IDENTIFIED ON A NUCLEUS OF MONTBELIARD BREED CATTLE EXPLOITED IN EAST OF ROMANIA

T. Bugeac, V.A. Bâlteanu, Şt. Creangă, L.D. Dascălu

Abstract
The aim of the current paper is to identify the genotypes, genotypes frequencies and alleles frequencies for the studied individuals. Based on our research, we identified common genetic variants for the six loci coding the major milk proteins: alpha-casein S₁ (αS₁-CN); beta-casein (β-CN); alpha-casein S₂ (αS₂-CN); kappa-casein (K-CN); beta-lactoglobulin (β-LG) and alpha-lactalbumin (α-LA). At αS1-CN locus, we identified only one genotype αS1-CN BB. For β-CN locus the A₂B genotype recorded the highest frequences (0.35), while in system αS₂-CN only one genotype was identified - AA, αS₂-CN A allele having a frequency of 1.00. For the K-CN locus, the AB genotype recorded the highest frequency (0.53). As for the whey proteins, at β-LG locus we identified three genotypes, the highest frequency being recorded by β-LG BB (0.62). In system (α-LA there is monomorphism for allele α-LA B. The milk samples analysis was made by the isoelectric focusing technique (IEF). The study was carried on a total number of 34 Montbeliard cows exploited in East of Romania.

Key words: Montbéliard breed, polymorphism, milk proteins, IEF, Roma