Still More Genetic Variability in Natural Populations

Abstract
Heat-denaturation studies of xanthine dehydrogenase have revealed many more additional alleles at the locus controlling this enzyme than are revealed by electrophoretic studies. In natural populations of species in the virilis group of the genus Drosophila, heat-denaturation studies of flies from the same locality revealed 1.74 times as many alleles as did electrophoretic studies. Similarly, studies of several species over their geographic range also revealed 1.74 times as many alleles. In addition, for the nine species studied, electrophoretic analysis had revealed only 11 alleles within the group, whereas heat-denaturation studies revealed a total of 32 alleles. These findings are discussed in the light of the continuing controversy over Darwinian and non-Darwinian theories of evolution.