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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 functioning during vulva formation have evolved substantially between these two nematodes. Most vulva defective mutants in Pristionchus pacificuscannot easily assigned for gene functions from the knowledge of C. elegans. To facilitate the cloning of these mutants we are generating genetic and physical maps of Pristionchus pacificus. Our work presented here is focussing on the construction of a genetic map using Dpy mutants. We screened 50,000 gametes and identified 50 dpy mutants. In order to map these mutants to the six chromosomes in Pristionchus pacificus, we are using the SNP markers of the genetic linkage map (Srinivasan et al, submitted). Of the 50 mutants, 34 have already been assigned to different chromosomes. Complementation analysis of 29 of these 34 mutants showed that they fall into 8 complementation groups. We are currently fine-mapping those dpy mutants with regard to the SNP markers. The remaining 21 dpymutants are currently assigned to individual chromosomes. We estimate a total number between 12 and 15 complementation groups with a dpy phenotype. In C. elegans, saturated screens identified 26 complementation groups with a dpyphenotype when mutated, 6 of which are located on the X chromosome. In contrast, in Pristionchus pacificus we find only one complementation group with one allele which assigned to the X chromosome. The data emanating from the genetic dpy map 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 carious screens, thereby establishing it as a second general nematode model system.