BRC-BIO: Exploring the genetic basis of adaptation through convergent dietary specialization in mammals

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Just as humans have many different cuisines, other mammals also have widely diverse dietary preferences, from antelope grazing the savannahs to polar bears hunting the fattest seals in the Arctic. We know very little about how and why these different diets have evolved, particularly about the genetic changes that allow mammals to eat so many different foods. This research project will first define mammalian diets using information from many sources. These sources include observations of mammals in the wild, measurements from museum specimens, and information about bacteria in animals’ guts. The researchers will then combine these specific dietary definitions with information about mammals’ DNA sequences to identify genes that are involved in the evolution of different diets. Finally, the researchers will use experiments to show how changes in different mammals’ genes affect cells’ ability to process components of their diets. This work will identify new genes that are important for mammals to adapt to their environments. It will show how changes in these genes have allowed mammals to process different foods. The project will also expand participation in genomics and bioinformatics research by historically excluded groups at both the K12 and undergraduate levels. Undergraduates from underrepresented backgrounds will work together with other scientists to carry out the research. The PI will also collaborate with K12 teachers in local high-need schools to develop activities that can bring genomic data into the teachers’ classrooms.Connecting genomic and environmental changes is key to understanding how adaptation proceeds. The investigation of convergent phenotypes, which provide independent replicates of the same adaptive process, holds particular promise for identifying genomic changes underlying adaptation. Observing molecular signatures of adaptation at the same genetic loci in multiple independent lineages with the same adaptive trait can implicate these loci as contributing to this trait. This proposal uses such signatures to identify genomic changes associated with convergent mammalian dietary changes. Specifically, the research will rigorously define quantitative phenotypes representing dietary variation across mammals. It will identify genes and gene families underlying selection on quantitative dietary phenotypes across mammals. Finally, the work will demonstrate the cellular mechanisms of metabolic genes involved in dietary adaptation. The PI’s lab will identify associations between the most variable quantitative dietary dimensions and the evolutionary rates of genes and gene families across the mammalian phylogeny, using publicly available data. To determine the functional impacts of observed evolutionary changes in specific metabolism genes, the lab will test the metabolic effects of different species’ orthologs in S. cerevisiae. Mammalian dietary adaptation involves changes in highly conserved intracellular metabolic pathways that are amenable to these functional assays. The methods, findings, and resources generated through this work will provide a foundation for future studies on the genomic basis of environmental adaptation across evolutionary timescales.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.