One of the aspects that seems to change very fast in evolution is the genetic mechanism that determines the sex of the animal. This is a proposal to study the genetic basis of sexual dimorphism in the nematode Pristionchus pacificus. The main goal is to functionally compare well-characterized sex determination gene homologues of the nematode Caenorhabditis elegans with P. pacificus. The study of related species should provide important information to understand how rapidly evolving pathways occur. This proposal makes use of the recently sequenced genome of P. pacificus and newly developed genetic technologies in this species. Genomic searches of Pristionchus genomes have identified five homologous genes involved in sex determination in C. elegans. Using a combination of genetic techniques, the function of these genes will be tested in P. pacificus. In parallel, sex determination mutants will be induced in this species. Although the identity of the genes involved in P. pacificus sex determination is difficult to predict, it is likely that they will be different from C. elegans. In this case, such fundamental questions as where these different genes come from, when were they integrated into the sex determination pathway and what is their function in C. elegans can be addressed. This research has a broad impact because will integrate research and education by involving undergraduate and graduate students, including different genders and underrepresented minorities. Furthermore, insights about mechanisms of sex determination in different nematodes can have practical value for sterilization of animal and plant parasites.
