Further genetic variation at the esterase loci of Drosophila virilis

Reexamination of the electrophoretic mobilities of esterases encoded by the Est- and the Est- alleles of Drosophila virilis was carried out in detail using both thin-layer agar gel and polyacrylamide slab gel electrophoresis. Many allelic products with fine differences in their electrophoretic mobilities were found and designated by a new system. Some esterases separable by the agar gel method were indistinguishable using the polyacrylamide gel method. But the polyacrylamide gel method uncovered two multiband homozygotes, ^(d).77 and ^(d)1.28. Some allelic frequencies on the basis of the new designation were estimated in two natural populations. As a result, it is proposed that the total scope of allelic variation at the two esterase loci of Drosophila virilis is composed of discrete distribution patterns of gene frequencies, each histogram of which shows a bell-shaped pattern.