Glossina morsitans morsitans and Glossina palpalis palpalis: dosage compensation raises questions about the Milligan model for control of trypanosome development.

Evidence that dosage compensation occurs in tsetse flies was obtained by comparing the activities of X chromosome-linked enzymes, arginine phosphokinase and glucose-6-phosphate dehydrogenase in Glossina m. morsitans and hexokinase and phosphoglucomutase in Glossina p. palpalis, with the activity of an autosome-linked enzyme, malate dehydrogenase, in each species. The shortcomings of the X chromosome model for the control of Trypanozoon maturation in tsetse are discussed in light of these findings and previously published reports on the lack of fitness effects of mature Trypanozoon infections in tsetse and on published results on antitrypanosomal factors in male and female tsetse flies.