Large-scale mapping of mutations affecting zebrafish development

Background: Large-scale mutagenesis screens in the zebrafish
employing the mutagen ENU have isolated several hundred mutant loci
that represent putative developmental control genes. In order to
realize the potential of such screens, systematic genetic mapping
of the mutations is necessary. Here we report on a large-scale
effort to map the mutations generated in mutagenesis screening at
the Max Planck Institute for Developmental Biology by genome
scanning with microsatellite markers. Results: We have selected a
set of microsatellite markers and developed methods and scoring
criteria suitable for efficient, high-throughput genome scanning.
We have used these methods to successfully obtain a rough map
position for 319 mutant loci from the Tubingen I mutagenesis screen
and subsequent screening of the mutant collection. For 277 of these
the corresponding gene is not yet identified. Mapping was
successful for 80 % of the tested loci. By comparing 21 mutation
and gene positions of cloned mutations we have validated the
correctness of our linkage group assignments and estimated the
standard error of our map positions to be approximately 6 cM.
Conclusion: By obtaining rough map positions for over 300 zebrafish
loci with developmental phenotypes, we have generated a dataset
that will be useful not only for cloning of the affected genes, but
also to suggest allelism of mutations with similar phenotypes that
will be identified in future screens. Furthermore this work
validates the usefulness of our methodology for rapid, systematic
and inexpensive microsatellite mapping of zebrafish mutations.