Further studies on the modifier gene system regulating activities of X-linked enzymes in Drosophila melanogaster.

Abstract

In a previous study, we reported the presence in Drosophila melanogaster of a modifier gene system which has influence on activities of three X-linked enzymes, G6PD, 6PGD and HAD. However, possibilities exist that the system may be primarily responsible for other traits which have influence on the enzyme activities. In order to examine these possibilities, the high- and low- activity lines established from a strain which is homozygous for an X chromosome were compared with respect to the following parameters: average size and total number of wing cells, protein, DNA and ribosomal RNA contents, total G6PD activity, distribution of G6PD, 6PGD and HAD activities, and synthetic and degradation rates of 6PGD. Effects of juvenile hormone and ecdysone on G6PD and 6PGD activities were also studied. The results obtained were all consistent with our assumption that the modifier gene system may be primarily responsible for the control of the X-linked enzyme genes.