Study of an association between SNP 775C>T within the bovine ITBG2 gene and milk performance traits in Black and White cows

Abstract

The exclusive pre-selective effect of BLAD carriers reproducing in the exposed Holstein-Friesian cattle population prompted to search for the candidate gene variants of high quality of milk performance traits within the bovine <i>ITBG</i>2 gene or loci linked with bovine <i>ITBG</i>2 gene. Theoretical considerations indicated that the &Idquo;silent mutation&rdquo; C&rarr;T localized at the position of 775 bp of the gene encoding the CD18 subunit might be a potential QTL marker of high milk productivity. An association study between the polymorphism of SNP 775C>T, and the diversification of milk performance traits was carried out on the progeny of four bulls with genotypes <i>BL/TL</i> and 775<i>C/T</i> and one bull with genotypes <i>TL/TL</i> and 775<i>C/T</i>. The results documented statistically significant differences in the protein content percentage of milk in two half-sib families of bulls with <i>BL/TL</i> and 775<i>C/T</i> genotype and one half-sib family of bull with <i>TL/TL</i> and 775<i>C/T</i> genotype. It was further concluded that the polymorphism of SNP 775C>T was found to be a more efficient QTL marker than that of D128G, since in all the analysed milk performance traits for half-sib families higher values of the F coefficient were obtained for the SNP 775C>T mutation in comparison with D128G.