The Use of Direct Genetic Markers K-Casein and DGAT1, Involved in Milk Production Characteristics

Abstract

Application of molecular markers for improved production relies on the ability to genotype individuals for specific genetic loci and to find the significant association between DNA polymorphism and important economic traits. Milk yield, milk composition, fat %, protein %, total solids and solids-non-fat are the most important characteristics in diary industry. Effects of K-casein and DGAT1 genes have been shown to be involved in the genetic determinism of these characteristics in cattle. The present study seeks a non-conservative substitution K232A (lysine by alanine) in the DGAT1 gene and for a point mutation, in a 350 bp fragment of kCN gene (exon IV), which distinguishes between the A from B alleles, the latter being desirable for cheese manufacturing. The genetic variation on these two loci was estimated in two cattle populations with different origins, in view of future studies to determine the effect of single gene and interaction effect of genotypes on milk yield and milk composition.