KOCHER, Thomas D; University of New Hampshire: From Natural Systems to Laboratory Models: Comparative Genomics of Teleost Fishes

The thousands of species of cichlid fishes in the lakes of East Africa are not only an evolutionary wonder, but also a natural mutant screen for phenotypes ranging from morphology to behavior. To facilitate genetic analysis of these natural mutants, we have developed a suite of genomic resources for African cichlids, including extensive genetic maps of microsatellite markers, and a physical map based on fingerprints of 35,000 BAC clones. We have also developed a variety of bioinformatics tools to relate these maps to the more completely sequenced genomes of pufferfish, medaka and zebrafish. Gene order is highly conserved among these fishes at scales of several megabases, which is facilitating the comparative positional cloning of genes for natural mutant phenotypes. Our studies have provided insights into how the developmental system is genetically modified to produce different trophic morphologies. Current work is aimed at identifying the genes underlying the rapid diversification of color patterns and sex-determining systems among these species. A similar comparative genomic approach would allow other fish species with interesting biology to be developed into practical laboratory models.