INTERACTIONS OF DIFFERENTIATED PRIMARY SEX FACTORS IN CHIRONOMUS TENTANS

Peter E. Thompson ¹ and Jean S. Bowen ¹

¹ Department of Zoology, University of Georgia, Athens, Georgia 30601

Different populations of Chironomus tentans, possibly representing geographically isolated races, have two differentiated genic mechanisms of sex determination involving either a dominant male-determining factor in the left arm of chromosome 1 or a dominant female-determining factor at the right tip of chromosome 1. In crosses between these populations, the male-determining factor is epistatic to the female-determining factor. No evidence of intersexuality has been found in such crosses.