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Abstract

Pristionchus pacificus has been established as a satellite organism for studying developmental processes and comparing them to C. elegans. Cell fate specification and gene function during vulva formation have evolved substantially between these two nematodes. Most vulva defective mutants in P. pacificus cannot easily be assigned for gene functions from the knowledge of C. elegans. To facilitate the cloning of these mutants we will generate genetic and physical maps of Pristionchus pacificus. Our work presented here is focussing on the construction of a genetic map using Dpy mutants. We performed a large scale EMS mutagenesis screen for dumpy mutants. We screened 50,000 gametes and isolated 177 dumpy mutants originally, 123 of which were re-identified. In order to map these Dpy mutants to the six chromosomes in Pristionchus pacificus we are using various Unc and vulva phenotypes as markers, i.e. the unc-22 homolog Ppa-unc-1 that defines chromosome IV and mab-5 that defines chromosome III. Crosses are ongoing. After mapping these mutants to the various chromosomes, we will perform complementation tests. The various complementation groups will be mapped onto the molecular genetic map using AFLP based linkage studies with the polymorphic strain P. pacificus var. Washington. The data emanating from the genetic and physical map projects will facilitate further genetic and molecular studies in Pristionchus pacificus. Specificially, the genetic dpy map will allow in-depth genetic characterization of mutants in Pristionchus pacificus isolated in various screens, thereby establishing it as a second general nematode model system.