Genomic Architecture of an Adaptive Radiation

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This research project considers the genetic mechanisms of vertebrate diversification from two perspectives. The first is that of population genetics. How many genes experience divergent selection during the evolution of new species? How are they distributed across the genome? The second perspective is that of the evolution of development. Which genes are modified to produce new phenotypes? The flock of some 800 closely related cichlids fishes in Lake Malawi are an ideal model system for this study. These species differ in the shape of their jaws and teeth, the color of their skin, and their mechanisms of sex determination. The genomes of 40 Metriaclima populations will be sequenced to quantify the proportion of the genome that has diverged among sister species. The genomes of 20 Labeotropheus populations will be sequenced and compared to Metriaclima to identify regions of the genome that have diverged between these genera that differ in craniofacial morphology. These data will provide the most comprehensive picture ever produced of the genomic architecture of speciation and adaptation in vertebrates. Analysis of these data will improve our understanding of the gene network controlling the development of neural crest cells, which contribute to a wide variety of pigmentation and craniofacial phenotypes unique to vertebrates. The project will also support a class in which undergraduate students will perform original research, and a summer workshop in which senior researchers will share the latest methods for analysis of cichlid genetics and development.