SGER: Population variation and environmental adaptation in all the genes of the purple sea urchin

Stanford University, Stanford CA

Investigators

Abstract

Environmental change in the oceans broadly impacts marine organisms and ecosystems, setting the limits of species' ranges, and determining the likely impact of future climate alteration. Many marine species persist over large geographic ranges: for example, of the 64 Large Marine Ecosystems - defined largely by dominant species - most span at least 20 degrees of latitude, and temperate LMEs often range from subtropical to northern temperate waters. Environmental gradients across these ranges are considerable, and so many key species in ecosystems live under spatially variable environmental regimes. High gene flow across these ranges in most marine species is expected to swamp out tight adaptation to environmental conditions. However, this assumption has never been rigorously tested for large numbers of traits or genes within any species. The investigator has developed a method to search the genome for genes affected by and adapted to environmental conditions, in order to obtain a complete picture of the way current environmental gradients affect the demography, life histories, and ecological role of critical species within ecosystems, impact organisms, and how future climate change will affect ecosystems. With this SGER, the investigator will test the utility of a new method he has developed to measure the impact of environmental gradients on every gene of a species' genome. The results should demonstrate a simple approach to rapid genetic identification of individuals at tens of thousands of loci at the same time. The investigator will use the purple sea urchin as the focal species because its genome has recently been completed and it shows intriguing patterns of population structure, but the approach we describe is broadly applicable to any species including humans.