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

The research article analyzes the genetic polymorphism, or the occurrence of various forms, of two specific proteins in horse serum: vitamin D binding protein and post-albumin protein. Researchers found that the types of both proteins are controlled by autosomal codominant alleles, and described a few distinct forms of these proteins in different horse breeds.

Methods used

• The study employed horizontal polyacrylamide gel electrophoreses, a method used for gene separation, using a 10% separation gel.
• This method was used on horse serum to identify the polymorphism of the Gc protein (vitamin D binding protein) and Pa protein (post-albumin protein).

Hypothesis and Results

• The observation from the family data led to the hypothesis that the types of both Gc and Pa proteins are determined by autosomal codominant alleles.
• For both proteins, the homozygous type (when two copies of the same allele are present) showed one single fraction, whereas the heterozygous type (when two different alleles are present) had two fractions.
• Pa types were found to be identical to the versions of post-albumin proteins reported earlier by starch gel electrophoresis, verifying this hypothesis.

Findings from Different Horse Breeds

• Two Gc variants, GcF and GcS, and three Pa variants, Pa D, Pa F, and Pa S, were found in samples from four breeds of Swedish horses, Lipizzaner, and Arabian horses.
• The frequencies of the more common allele at both loci (i.e., GcF and PaF) ranged from 0.72-0.93 and 0.58-0.99, respectively, in the various breeds studied.

Limitations

• The study found that plasma samples were unsuitable for Gc typing as they displayed an extra protein fraction near the GcS fraction.