Global coral genomic vulnerability explains recent reef losses

The dramatic decline of reef-building corals calls for a better understanding of coral adaptation to ocean warming. Here, we characterized genetic diversity of the widespread genus Acropora by building a genomic database of 547 coral samples from different oceanic regions—from the Great Barrier Reef to the Persian Gulf. Through genome-environment associations, we found that different Acropora species showed evolutionary signals of heat-adaptation in the same genomic regions, pointing to genes associated with molecular heat shock responses and symbiosis. These adaptive signals were uncommon in Acropora populations exposed to less than two heatwaves, indicating a potential genomic vulnerability to future heat exposure. We showed that genomic vulnerability estimates corroborate local and global patterns of coral decline, and used these estimates to reassess global coral reef conservation risks and priorities.