Polymorphism within theLDHA gene in the homing and non-homing pigeons

Abstract

A total of 445 domestic pigeons were genotyped for the lactate dehydrogenase (LDHA) gene. Crude DNA was isolated from blood samples and feathers. Two polymorphic sites were identified in intron 6: one near the splice donor site GT is called site H and the other near the splice acceptor site is called site B. Interestingly, the nucleotide changes of both these sites associate perfectly with theA andB alleles ofHaeIII polymorphism: theA allele with nucleotide A of site H and nucleotide T of site B; while theB allele with nucleotide G of site H and nucleotide G of site B. In this study, we have identified the molecular difference between allelesA andB of the pigeonLDHA gene. The difference at site H in intron 6 explains theHaeIII polymorphism. The frequencies ofLDHA ^AB andLDHA ^BB genotypes between the analysed groups differ significantly (P < 0.001); theLDHA _A allele was more frequent in the groups of pigeons with elevated homing performance (P < 0.001). The functional difference may be due to the change at site B, the potential splice branch site. Since LDHA activity is associated with the homing ability, it is possible that during the process of selection for the homing ability, theLDHA ^A allele has been selected, and is more prevalent in the top-racing groups.