Molecular genetics of avian proteins—V. Egg, blood and tissue proteins of the ring-necked pheasant, Phasianus colchicus L.

Abstract

1. 1. Egg white proteins, egg yolk proteins, haemoglobin, serum proteins, muscle proteins and enzymes from Phasianus colchicus have been examined by starch gel electrophoresis and, in some cases, by other biochemical techniques. Comparisons were made between the proteins of P. colchicus and the proteins of related species, especially P. versicolor and Gallus gallus on an individual basis. 2. 2. A number of protein fractions have been identified. Some, such as the egg-yolk proteins, haemoglobin and myoglobin, are essentially conservative; other fractions are very variable. Particular attention was paid to the variation of the iron-binding proteins of egg white (conalbumin) and of serum (transferrin); serum prealbumins; and serum esterases. 3. 3. Conalbumin and transferrin are not identical but, in addition to their binding of iron, resemble each other in the pattern of variation. Individual birds have one of three transferrin types: “slow”, “fast” and heterozygous. Laying hen pheasants produce conalbumin types which match their transferrin types. It is suggested that the variation of the iron-binding proteins is controlled at a single locus with a pair of codominant genes. 4. 4. One group of serum prealbumins, designated here “region II”, contains three sharp protein zones: A, B and C. No more than two of these bands occur in any one bird; the existence of six phenotypes suggests a single genetic locus with three alleles. 5. 5. An extremely complex serum esterase variation was observed which could not be classified into well-defined genetic types. The qualitative and quantitative variation of pheasant esterases, considered with published information concerning pesticide resistance in various species, suggests that serum esterase polymorphism may contribute to the success of the pheasant in regions where other avian species are adversely affected by pesticide residues. 6. 6. The variation of pheasant proteins is discussed in connexion with the evolution of the pheasant as an introduced game bird.