Enzyme variability in the Drosophila willistoni group. VI. Levels of polymorphism and the physiological function of enzymes.

We have studied allelic variation at 28 loci coding for soluble enzymes in three sibling species of Drosophila. The average proportion of polymorphic loci per population is 58% in D. willistoni, 71% in D. equinoxialis, and 60% in D. tropicalis. An individual of any one of these three species is heterozygous at 18-22% of its genes. The correlation between the amount of polymorphism at a given locus and the equilibrium constant of the reaction catalyzed by the corresponding enzyme is not significantly different from zero. We have separated enzymes into those involved in glucose metabolism (group I) and all other enzymes (group II). The genes coding for group II enzymes are about twice as polymorphic as those coding for group I enzymes. © 1972 Plenum Publishing Corporation