Adaptation to climate gradients

A potential evolutionary response to rapid environmental change is adaptation of local populations. In high gene flow systems like marine environments, local adaptation was traditionally thought to be rare, but the recent rise of genomic data has led to the discovery of environmentally-associated genetic structuring in panmictic populations. We have examined adaptation across a small spatial scale in corals, finding 114 genetic variants within the Acropora hyacinthus transcriptome significantly associated with temperature at adjacent sites with different thermal regimes (Bay & Palumbi 2014 Curr Biol). We also performed a reciprocal transplant study and found that corals from the more thermally variable site had higher survivorship, suggesting that the extreme environment filters for high surviving, thermally tolerant genotypes (Figure below). However, there was a general tradeoff between survival and growth, which likely maintains polymorphisms within the population (Bay & Palumbi Ecol Evol).
We currently work in collaboration with the Bird Genoscape Project at UCLA, examining climate-associated genetic variation in migratory songbirds. We use genome scans to examine population structure and climate adaptation across North America. This allows us to identify which climate parameters are most important in structuring genetic variation across the species range and which genomic regions are involved in climate adaptation (Bay et al. 2018 Science; Ruegg et al. 2018 Ecology Letters). Additionally, collaborators on the Bird Genoscape Project use population structure and assignment analysis to map migratory flyways between North American breeding grounds and wintering locations. One interesting application of this project is that we have been working with renewable energy companies to genotype of carcasses collected at solar and wind farms and measure population-specific impacts of these facilities and inform operational mitigation of avian mortality.

Publications

. Comparative analysis of the Pocillopora damicornis genome highlights role of immune system in coral evolution. Scientific Reports, 2018.

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. Ecological genomics predicts climate vulnerability in an endangered southwest songbird. Ecology Letters, 2018.

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. Mechanisms of thermal tolerance in reef-building corals across a fine-grained environmental mosaic: Lessons from Ofu, American Samoa. Frontiers in Marine Science, 2018.

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. Parallel introgression and selection on introduced alleles in a native species. Molecular Ecology, 2018.

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. Polygenic evolution drives species divergence and climate adaptation in corals. Evolution, 2018.

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. Genomic signals of selection predict climate-driven population declines in a migratory bird. Science, 2018.

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. Genomic models predict successful coral adaptation if future ocean warming rates are reduced. Science Advances, 2017.

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. Predicting responses to contemporary environmental change using evolutionary response architectures. The American Naturalist, 2017.

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. Mechanisms of reef coral resistance to future climate change. Science, 2014.

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