Genomic Signatures of Natural Selection and Adaptation to Climate Change in the Sea

A key question about climate change is the extent to which natural selection and adaptation may help populations evolve new environmental tolerance during rapid shifts in temperature and ocean acidity. Data on divergence patterns are beginning to come from genome-wide comparsions, and can show how selection accelerates divergence across the genome. We compared the genomes of two sea urchins, the shallow water Strongylocentrotus purpuratus with the deep sea Allocentrotus fragilis for patterns of rapid protein evolution. Genes involved in biomineralization, which is expected to be more difficult in the future due to ocean acidification, are evolving much more quickly in the deep water Allocentrotus, perhaps because deep waters are already acidic. Similar data on the population divergence of S. purpuratus along the US west coast shows that biomineralization genes are more likely to be diverged in allele frequencies. In this case, selection on genes involved in skeletal formation seems higher than selection on genes in other metabolic pathways. If high genetic divergence reflects increased balanced polymorphism due to spatial differences in natural selection, then evolution in the face of future acidification may be rapid.

Speaker: Stephen Palumbi

Room 2040