Restoration of mutationally suppressed characters in Drosophila melanogaster

We examined three strains of Drosophila melanogaster made wingless for periods of up to 40 years by homozygosity for the recessive mutant, vestigial. The intent was to quantify the degeneration of genes for wing structure and function that were not expressed during these periods. No increase in abnormality of wing morphology or use was found in the oldest strains despite up to 1000 generations of winglessness. We propose that these genes have remained intact because of important pleiotropic effects not connected with wing formation.