We study several fundamental issues in evolutionary biology. In particular, the evolution of biodiversity, and specifically the genesis of genomic, developmental and morphological diversity as well as their evolutionary interconnections, are of interest to us. To this end we study: (1) morphological differentiation and its developmental basis within a phylogenetic framework, (2) genetic differentiation among populations and species, and (3) the evolution of genes and genomes, and the evolution of novel gene functions. In an effort to better understand the origin and maintenance of diversity we mostly use molecular and bioinformatic approaches, to ask how many and what kind of genetic changes accompany morphological differentiation among populations, separates species, and which molecular evolutionary processes lead to the diversification in sequence and function of genes within gene families and among genomes.
In order to address these central issues in evolutionary biology we are conducting multidisciplinary, integrative research. The laboratory is equipped with state-of-the-art fish facilities for zebrafish and cichlids, developmental as well as molecular biology and genomic equipment including two ABI 3100 automatic DNA sequencers, a DNA-Chip reader, and a pipetting robot. The methodological approaches used in the lab range from population genetics, phylogeography and phylogenetics, molecular evolution and comparative genomics, including DNA-chip technologies and EST-studies, to developmental work the connections between ontogenetic diversification and evolution. Our model organisms are mostly fishes, especially zebrafish and cichlids, but also include frogs among various other groups of animals. The genes of most interest to us are genes that control developmental processes. Ongoing projects address issues that connect developmental and evolutionary problems by comparing developmental mechanisms between the zebrafish and cichlid fishes and aim to identify novel genes that are responsible for species-specific differences in the head morphology and coloration of different species of cichlids fishes. The range of techniques that are being used in the lab mirrors the diversity of questions and approaches in this lab. For the behavioral questions experiments on the behavioral ecology of fish are being conducted in the lab and in the field (e.g. paternity analysis). Studies on sexual selection and speciation in cichlid fishes are being carried out through behavioral and ecological experimentation and through comparative genetic analyses. Several ongoing projects involve DNA sequence analyses for evolutionary questions above the species level and molecular phylogenetic and molecular evolutionary analyses concerning the evolution of families of developmental control genes and their evolutionary diversification in function.
Past studies include work on the evolution, particularly speciation, genetic differentiation and phylogeny of cichlid fishes in the East African cichlid radiations where, amongst other things, we documented explosive rates of speciation, widespread parallel evolution in morphological, ecological and behavioral traits, and the importance of paleoclimatological influences on intralacustrine speciation patterns. Work on the evolution of tetrapods focused on lungfish-coelacanths, amphibians and amniote relationships. For example, our results demonstrated that the lungfish rather then the textbook favorite, the coelacanth, is the closest living relative among fishes to the land vertebrates. Several other molecular ecological, molecular phylogenetic and comparative genomic projects with an emphasis on fishes and projects on the evolution of developmental control genes such as Hox genes and hedgehog genes have been conducted.
Please consult the www pages of individual lab members for more details on past and ongoing studies.