Molecular genetics of avian proteins XIII.Protein polymorphism in three species of australian passerines

Abstract

An introduced species, the house sparrow (Passer domesticus), and two Australian native species, the welcome swallow (Hirundo tahitica neoxena) and the fairy martin (Petrochelidon ariel), have moderately low levels of protein polymorphism compared with domesticated or semi-wild 'managed' species of birds. Genetically variant proteins in these birds include transferrin, esterase, phosphoglucomutase, NADP-dependent isocitrate dehydrogenases, phosphogluconate dehydrogenase (decarboxylating) and glucose-6-phosphate dehydrogenase. Egg-white protein polymorphism confirms heterogeneity of eggcolour, markings and shape, and suggests that approximately 10% of the ‘clutches’ in house sparrow nests represent infidelity (intraspecific nest parasitism). For the four enzymes capable of supplying reduced NADP for reductive biosynthesesin growth and detoxification, the house sparrow has more heterozygosity (2.9 %) than either the welcome swallow (9.4 %) or the fairy martin (2.3 %) and the difference is highly significant statistically. The results are discussed in relation to possible biochemical correlates of MacArthur and Wilson’s (1967) evolutionary strategies of r or K selection. © 1975 ASEG.