FOUR PROTEIN POLYMORPHISMS IN PIGEON BRAIN EXTRACTS DETECTED BY TWO-DIMENSIONAL GEL ELECTROPHORESIS

Abstract— Proteins of the brain extracts of 85 individual pigeons (Columba livia) were mapped by two-dimensional gel electrophoresis. The method is a modification of O'Farrell 'S technique and separates proteins first by charge and then by molecular weight. There were three proteins, A, B and D which had each a variant form. The positions of these six proteins on the gel corresponded to the following pH values and molecular weight values: protein A₁, 6.4/43,000; A₂, 6.6/43,000; B₁, 5.7/41,000; B₂, 5.8/40,000; D₁, 6.2/22,000; D₂, 6.2/21,000. The variants are genetically determined, since protein A, B and D each occurred in three phenotypes (A₁, A₁A₂ and A₂; B₁, B₁B₂ and B₂; D₁, D₁D₂ and D₂) corresponding to the three possible genotypes. From the observed frequencies of the phenotypes the following allele frequencies were calculated: allele A₁, 72%; A₂, 28%; B₁, 15%; B₂, 85%; D₁, 74%; D₂, 26%. A fourth protein named C occurred in four different forms (C₁, 7.2/37,000; C₂, 7.2/36,000; C₃, 7.1/37,000; C₄, 7.1/36,000) and six phenotypes (C₁, C₁C₂, C₂, C₁C₃, C₂C₃ and C₄C₃). This polymorphism is also interpreted as being genetically determined. The four alleles coding for the four protein C forms had the following frequencies: allele C₁, 62%; C₂, 27%; C₃, 10.5%; C₄, 0.5%.