VIVE-LA-DIFFERENCE - MALES VS FEMALES IN FLIES VS WORMS

For 600 million years, the two best-understood metazoan species, the n ematode Caenorhabditis elegans and the fruit fly Drosophila melanogast er, have developed independent strategies for solving a biological pro blem faced by essentially an metazoans: how to generate two sexes in t he proper proportions. The genetic program for sexual dimorphism has b een a major focus of research in these two organisms almost from the m oment they were chosen for study, and it may now be the best-understoo d general aspect of their development. In this review, we compare and contrast the strategies used for sex determination (including dosage c ompensation) between ''the fly'' and ''the worm'' and the way this und erstanding has come about. Although no overlap has been found among th e molecules used by flies and worms to achieve sex determination, stri king similarities have been found in the genetic strategies used by th ese two species to differentiate their sexes.