Meeting Abstract

85.3  Thursday, Jan. 7  The purple sea urchin genome suggests local adaptation along a latitudinal gradient despite high gene flow. PESPENI, M.H.*; PALUMBI, S.R.; Stanford University; Stanford University mpespeni@stanford.edu

Identifying adaptive genes is a central challenge in evolutionary biology, especially when high dispersal disrupts the signal of local adaptation. Here we develop a new SNP genotyping method with >99% accuracy and scan the genome of a species with a highly open population structure, the sea urchin Strongylocentrotus purpuratus. We assayed 50,935 loci, identifying 12,431 SNPs, and finding approximately 100 – 300 (1 – 2.5%) with excess divergence. Gene ontology and stage-specific expression data show a greater proportion than expected of these diverged genes act strictly during larval development. Our SNP detection method shows that adaptive evolution in purple urchins occurs across a small but significant fraction of the genome and suggests that early life history stages are a critical place to search for the action of environment on fitness.