Reconstructing evolutionary history in adaptive radiations with genomic data

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Evolutionary biologists seek to understand why there is such tremendous diversity in life forms and how these diverse forms developed over time. One approach to addressing these questions is to study and compare the genetic makeup of closely related species. Some of life's most striking examples of diversity have evolved in a process known as adaptive radiation, when a wide variety of closely related species arise from a common ancestor during a relatively brief period of time. Adaptive radiations of cichlid fishes in certain African lakes provide captivating examples of this process, where these fishes exhibit incredible diversity in color, shape, and reproductive and feeding behaviors. Recently developed technologies make it easier to obtain large amounts of genetic data from wild organisms, so that it is now possible to document thousands of times more of the genetic makeup of these species than ever before. This project will use such genomic data to study the history of species that have formed in two African cichlid fish adaptive radiations, thus improving our understanding of how and why species have evolved, and yielding greater insight into the origins of biodiversity. In addition to its scientific goals, this work will strengthen relationships with international partners in Tanzania and the Democratic Republic of Congo through a collaborative workshop on the use of genetic data in understanding and monitoring biodiversity. It will also involve the development of educational materials for teaching about evolution and biodiversity in middle school classrooms. Adaptive radiations are exemplary systems for studying evolutionary processes due to the diversity of forms that evolve on rapid timescales. However, the rapid nature of these diversification events means that reconstructing the history of species divergence can be intensely challenging. The recent attainability of genome-wide sequence data for non-model organisms has precipitated a fundamental shift in the data that can be used to address questions related to the history of rapidly diversifying species. Such genomic datasets present new opportunities for uniting population genetics approaches with phylogenetic approaches to understand the history of species and speciation in adaptive radiation. This research will expand knowledge of how genomic data can aid in reconstructing the history of rapid adaptive radiations by studying two model cichlid adaptive radiations, Lake Kivu's haplochromine cichlids and Lake Tanganyika's tropheine cichlids. It will use newly available genomic resources to investigate the evolutionary history of these groups and the evolutionary processes influencing patterns of genetic diversity.