REGULATION OF GENE FUNCTION: A COMPARISON OF X-LINKED ENZYME ACTIVITY LEVELS IN NORMAL AND INTERSEXUAL TRIPLOIDS OF DROSOPHILA MELANOGASTER

Abstract

ABSTRACT We have measured gene function in normal and male-like intersexual triploids of Drosophila melanogaster by assaying crude extracts of whole flies or thoraces for levels of an X-linked (6-phosphogluconate dehydrogenase) and an autosomal (NADP-dependent isocitrate dehydrogenase) enzyme activity. Our observations lead us to conclude that each dose of the X-linked gene is more active in the cells of these intersexes than it is in normal triploid or diploid female cells. These results indicate that a level of activity intermediate between the normal male and female levels is possible for X-linked genes.