Genetic polymorphism of the vitamin D binding protein and another post-albumin protein in horse serum

Horizontal polyacrylamide gel electrophoresis, on 10% separation gel, of horse serum revealed polymorphism of the vitamin D binding protein (Gc protein) and another post-albumin protein (Pa). Family data supported the hypothesis that Gc and Pa types were controlled by autosomal codominant alleles. For both Gc and Pa proteins, the homozygous types showed a single fraction while the heterozygous type had two fractions. Pa types were found to be identical to the post-albumin types reported earlier by starch gel electrophoresis. Two Gc alleles, Gc F and Gc S , and three Pa alleles, Pa D, Pa F and Pa S , were observed in samples from Swedish (four breeds), Lipizzaner and Arab horses. The frequency of the more common allele at the two loci, i.e. Gc F and Pa F , ranged from 0.72–0.93 and from 0.58–0.99, respectively, in the different breeds studied. Plasma samples showed an extra protein fraction near the Gc S fraction and thus were found unsuitable for Gc typing.