Across the animal kingdom, pigmentation patterns are subject to change in novel and fluctuating environments. Color variation among cichlid fish in the East African Great Lakes is a hallmark driving their speciation in one of the largest adaptive radiations recorded among vertebrates. This project will explore how a "molecular switch", DNA methylation, can change the function of genes in the pigment cells of a color-changing cichlid fish adapting to the algal blooms of Lake Tanganyika. The study of these reversible color changing processes will improve the understanding of the fluidity that exists between a static genome and an animals' need to adapt to an ever-changing environment. The principal investigator (PI) will carry out this research at an institute that primarily serves under-represented minorities in science at the undergraduate and graduate level in the largest most ethnically diverse urban area in the world. In addition to training opportunities in his laboratory, the PI will share the relevance of environment-by-gene interactions to underprivileged youths during two-week workshops held in Santiago, Chile, where the PI will teach the relevance of the genetic determinants that affect human health and disease and the plastic molecular mechanisms that change with socio-economic position, adversity, and mental illness.
Animal pigmentation is a salient trait across the animal kingdom that allows an individual to become cryptic, predatory, or sexually attractive. The project will use Astatotilapia burtoni, an African cichlid fish, with robust and reversible color morphs to develop the understanding of the role DNA methylation plays in the function of pigment-bearing cells during changes in pigmentation. Previous work by this PI has shown that these morphs are accompanied by alterations in DNA methylation of the Endothelin Receptor B promoter and this project will expand this role in the field, across the genome, and through their upstream signaling cascades. Using a combination of satellite imaging, in situ measurements of lake morphology, high throughput sequencing, pharmacology, and cell sorting, the project will characterize and dissect this ecologically relevant trait that is ubiquitous throughout the animal kingdom. The strength of this proposal lies within its interdisciplinary integration of environmental measures in the field to reveal a comprehensive understanding of visual ecology with experimental validation carried out in the laboratory. The project will also resolve the function of pigment-bearing cells across an entire animal into enriched cell populations that directly correspond to the trait in question, thus eliminating hurdles of cell heterogeneity that typically limit the interpretation of these studies. It is anticipated that the findings from this study will be widely relevant to the field of evolution, visual ecology, and cellular biology.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
