Genetic Polymorphism of Milk Proteins in Hungarian Spotted and Hungarian Grey Cattle: A Possible New Genetic Variant of β-Lactoglobulin

Genetic variants of O:'s\-' 13-.and ,,caseins and of 13-lactoglobulin were studied with PAGE and isoelectric focusing in milk samples of 101 Hungarian Spotted and 120 Hungarian Grey cows.Gene frequencies and genotypic frequencies were estimated.Significant differences in gene frequencies between the two breeds were observed at the K-casein and 13lactoglobulin locus.The variants 13casein e, ,,-casein e, and 13-lactoglobulin D were not found in Hungarian Grey cows.On immobilized pH gradient, isoelectric focusing gels containing carrier ampholytes, a new unidentified protein band appeared near 13-lactoglobulin B in about 10% of the milk samples of Hungarian Grey cattle.(Key words: milk protein, genetic polymorphism, Hungarian cattle) Abbreviation key: CA-IEF = isoelectric focusing in the presence of carrier ampholytes, CA-IPG-IEF = isoelectric focusing in immobilized pH gradients in the presence of carrier ampholytes, CN =casein (used with O:'sr.O:'s2-, 13-, and K-).HG =Hungarian Grey, HS = Hungarian Spotted, LG =lactoglobulin (used with 13-).