EVOLUTION OF NEMATODE VULVAR FATE PATTERNING

Nematodes provide a useful experimental system with which to investiga te the evolution of development at the cellular, genetic, and molecula r levels. Building on an understanding of vulval development in Caenor habditis elegans, analysis of vulval development has been extended to a number of other species in three families of the Nematode phylum. Ch anges have occurred in most aspects of vulval development: alteration in the number of cells competent to participate in vulval development by changes in apoptosis; changes in the relative contributions of posi tion-dependent predisposition toward particular fates (prepattern), in ductive signaling and lateral signaling; and in the specific lineages generated by vulval precursor cells. Genetic analysis of one species i n which only three vulval precursor cells are present identified a mut ation that increases the number of vulva precursor cells toward that f ound in C. elegans. (C) 1996 Academic Press, Inc.