Population genetics of the coral Acropora millepora : Toward genomic prediction of bleaching

Corals worldwide are under threat from rising sea temperatures and pollution. One response to heat stress is coral bleaching—the loss of photosynthetic endosymbionts that provide energy for the coral. Fuller et al. present a high-resolution genome of the coral Acropora millepora (see the Perspective by Bay and Guerrero). They were able to perform population genetic analyses with samples sequenced at lower coverage and conduct genome-wide association studies. These data were combined to generate a polygenic risk score for bleaching that can be used in coral conservation. Science this issue p. eaba4674 ; see also p. 249 A high-quality genome analysis of a branching stony coral helps elucidate the genetics of coral bleaching. Although reef-building corals are declining worldwide, responses to bleaching vary within and across species and are partly heritable. Toward predicting bleaching response from genomic data, we generated a chromosome-scale genome assembly for the coral Acropora millepora . We obtained whole-genome sequences for 237 phenotyped samples collected at 12 reefs along the Great Barrier Reef, among which we inferred little population structure. Scanning the genome for evidence of local adaptation, we detected signatures of long-term balancing selection in the heat-shock co-chaperone sacsin . We conducted a genome-wide association study of visual bleaching score for 213 samples, incorporating the polygenic score derived from it into a predictive model for bleaching in the wild. These results set the stage for genomics-based approaches in conservation strategies.