Allele and genotype frequencies of
-lactoglobulin gene in Iranian Najdi cattle and buffalo populations using PCR-RFLP

Abstract

In modern programmes of animal breeding, the polymorphism of the milk proteins can be used as marker systems.

-Lactoglobulin is the major milk whey protein in the ruminants. Studies have indicated that this protein is polymorphic in the many breeds of cattle. This is the result of a single base pair substitution in the -lactoglobulin gene that also give rise to the Hae III restriction fragment length polymorphism. The aim of this work was to analyze the genotype distribution of -lactoglobulin in Iranian Najdi cattle and buffalo. Blood samples were supplied from 80 Najdi cattle and 80 buffalo from different cities of Khouzestan province. Polymerase chain reaction was applied to amplification of a 247 bp fragment of exon and intron IV of bovine -lactoglobulin gene. The Hae III enzyme was used for restriction of the PCR products. The digested products were separated by electrophoresis on 2.5% agarose gel. The allele B of -Lactoglobulin occurred at a higher frequency than the allele A in both Najdi cattle and buffalo. The genotype frequencies of AA, AB, and BB in Najdi cattle and buffalo were 0, 0.175, 0.825 and 0.04, 0.3, 0.66 respectively. Frequencies of A and B alleles were 0.0875 and 0.9125, and 0.1875 and 0.8125 in Najdi cattle and buffalo, respectively. The deviation from Hardy-Weinberg equilibrium was not detected in any of those animals. Detection of heterozygosity indicator evidence on low level of heterozygosity and genetic variability in both populations