FWF-Project P22737-B09

Summary

During the last two decades cichlid fishes have been established as evolutionary model system. Genomic approaches have undergone massive innovation concerning speed and efficiency of deciphering whole genomes and become increasingly important in evolutionary biology. My research group has been studying the adaptive radiation of cichlid fishes for more than 15 years, attempting to understand the pathways of speciation and adaptation to novel ecological niches. The cichlid fishes of Lake Tanganyika represent the oldest and eco-morphologically most advanced adaptive radiation and several lineages radiated in parallel. We chose the tribe Tropheini to study adaptive evolution, as they are much more diverse in terms of ecology, morphology and behavior than any Lake Malawi and Victoria cichlid, despite being part of a monophyletic and closely related assemblage. To take our approach further in evo-devo context, we propose to decipher the genomes of two highly divergent members of the Tropheini, the epilithic algae feeder Tropheus moorii, and the unicellular algae comber Petrochromis trewavasae. We intend to use 454 sequencing technology in combination with shotgun approaches to successfully score the two genomes in reasonably complete coverage. The project is planned as cooperation between three research groups from three Universities, The Karl-Franzens University of Graz, The Medical University of Graz, and the Graz University of Technology, whereby each group contributes crucial expertise and resources. The team-members of the Department of Zoology provide the study system and the research questions and hypotheses, the partners of the Center of Medical Research of the Medical University of Graz contribute their powerful genome sequencing unit, the members of the Institute for Genomics and Bioinformatics provide their expertise in genome assembly and annotation and computing infrastructure, which can cope with the demands of sequencing large genomes. This project should not be understood as an attempt to undermine ongoing efforts in cichlid genomics, but as a valuable complement in the common goal to decipher a suite of wisely chosen cichlid genomes as “natural mutants”, to understand the common pattern of cichlid adaptive evolution and its connection to speciation processes at various stages of adaptive radiation. By comparing particular structural and regulatory genes in addition to the genome sequencing effort we hope to find correlates to divergent eco-morphologies, as recently demonstrated e.g. for Lake Malawi rock cichlids. The advantage and complementary potential of the Lake Tanganyika system would be its significantly older evolutionary age and the fact of more complete genomic separation, mirrored in the completed lineage sorting among species in the mtDNA genome.