Genetic polymorphism of the vitamin D-binding protein and a pre-transferrin in chicken plasma

Two-dimensional agarose gel (pH 8.6)-polyacrylamide gel (pH 9.0) electrophoresis of chicken plasma was performed. In the β region, one major protein was identified as vitamin D-binding protein (VDBP), and another major protein was a protease inhibitor. Three phenotypes of VDBP were observed in Rhode Island Red and in New Hampshire breeds. The electrophoretic patterns and phenotype frequencies of VDBP indicated that this polymorphism was controlled by two codominant, autosomal alleles. The two VDBP homozygote types showed 2 fractions each, while the VDBP heterozygote type showed 4 fractions. Genetic polymorphism was also observed for an unidentified protein, tentatively designated as pre-transferrin (Prt). Some of the chickens had this protein, while the others were lacking in this protein. The analysis of family data suggested that the Prt polymorphism was controlled by two autosomal alleles. The allele causing occurrence of Prt fraction appeared to be dominant over the other allele.