A Serum Amylase Polymorphism in Populations of the Brush-Tailed Possum Trichosurus Vulpecula

Abstract

During the last ten years, the techniques of gel electrophoresis have revealed a large amount of heritable biochemical variation in populations of many organisms. Lewontin and Hubby (1966) have estimated that on the average 30% of all loci are heterozygous in natural populations of Drosophila pseudoobscura, and similar estimates have been obtained for other species of Drosophila (O'Brien and MacIntyre 1969) and for man (Harris 1966). The ecological and evolutionary significance of this variation is as yet almost completely unknown. An experimental approach to this problem is to study the nature and extent of variation within and between samples from subpopulations of a single species, and to relate this variation to environmental factors and breeding structure. This approach has indicated the nature of the selection on several morphological polymorphisms (Sheppard 1959; Kettlewell 1965) but with the exception ofthe sickle cell haemoglobin polymorphism in man (Allison 1954) it has provided little evidence concerning the factors affecting biochemical polymorphisms.