Meeting Abstract

36.1  Thursday, Jan. 5  Sex determination in a nematode that produces males, females and hermaphrodites PIRES DA SILVA, Andre; Univ. of Texas at Arlington, Arlington

The evolution of mating systems has fascinated biologists since the time of Darwin, specifically the causes and consequences of a species transition from one mating system (e.g. dioecy) to another (e.g. hermaphroditism). Theory predicts that these transitions likely involve one or more intermediates. To understand how animals transition from one mating system to another, we are studying the mechanisms by which the nematode Rhabditis sp. SB347 generates male, female and hermaphrodite progeny. We found that the male /non-male decision is chromosomally determined, whereas the hermaphrodite/female decision seems to be non-genetic. A pheromone secreted by siblings, or the lack of cholesterol, can convert a female-fated animal to develop into a hermaphrodite. The study of the molecular mechanisms underlying sex determination in this and other closely species might shed some light in how mating systems evolve.