As evolution progresses, developmental changes occur. Genes lose and gainmolecular partners, regulatory sequences, and new functions. As a consequence, tissuesevolve alternative methods to develop similar structures, more or less robust. How thisoccurs is a major question in biology. One method of addressing this question is byexamining the developmental and genetic differences between similar species. Severalstudies of nematodes Pristionchus pacificus and Oscheius CEW1 have revealed variousdifferences in vulval development from the well-studied C. elegans (e.g. gonad induction,competence group specification, and gene function.)
I approached the question of developmental change in a similar manner by usingCaenorhabditis briggsae, a close relative of C. elegans. C. briggsae allows the use oftransgenic approaches to determine developmental changes between species. Wedetermined subtle changes in the competence group, in 1° cell specification, and vulvallineage.
We also analyzed the let-60 gene in four nematode species. We foundconservation in the codon identity and exon-intron boundaries, but lack of an extended 3'untranslated region in Caenorhabditis briggsae.
