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Abstract

We are studying the evolution of cell fate specification, using vulva development as a model system and compare C. elegans with Pristionchus pacificus. We performed various genetic screens to isolate a number of mutants defective in vulva formation, many of which result in phenotypes unknown in C.elegans. To facilitate the molecular characterization of these mutants, we have initiated a physical and genetic map project of Pristionchus pacificus. The Pristionchus genome is approximately 100 MB in size. We have constructed a BAC library (with the help of Keygene N.V., Netherlands) with approximately 14 fold coverage of the Pristionchus genome and have performed BAC end sequencing (in collaboration with the Genome Sequencing Center, MPI Tuebingen) for half of the clones. We are using the sequence information from the BAC ends to create a polymorphism map using the strain Pristionchus pacificus var. Washington. It has been observed that the Washington strain shows a high degree of polymorphism with respect to Pristionchus pacificus var. California. The AFLP analysis indicated 55% of the bands (368 of the 630 bands) to be polymorphic between the two populations (Srinivasan et al, 2001). More than 1,000 BAC ends were tested for polymorphisms using the Single Stranded Conformation Polymorphism (SSCP) technique. 200 of the polymorphic markers were used to construct a genetic linkage map. The two parental strains from California and Washington were crossed and genetic marker segregation was followed in 48 random F2 offspring for each of the 200 polymorphic markers thereby generating a genetic linkage map. We also have initiated to construct a restriction fingerprint map of Pristionchus. Combining the polymorphism data, the genetic linkage map and the restriction fingerprint map will facilitate the cloning of mutants in Pristionchus pacificus.