By combining genomic and environmental data on coral reefs, a team led by Columbia University scientists have developed a model for predicting coral bleaching, a stress event triggered by increased water temperatures and linked to climate change. The investigators generated a chromosome-scale genome assembly for the coral Acropora millepora, which they compared with whole-genome sequences for 237 phenotyped samples collected at 12 reefs along the Great Barrier Reef. Among their findings, which appear in Science, was a notable amount of genetic diversity in the heat-shock co-chaperone sacsin, providing evidence of local environmental adaptation. The researchers also developed a polygenic score based on a genome-wide association study of visual bleaching score for 213 samples, which they incorporated into a predictive model for bleaching in the wild. The study, they conclude, demonstrates the feasibility of high-quality genome assembly, imputation, and genome-wide association studies in a nonmodel organism, and "highlights the potential of combining genomic and environmental data to predict phenotypes of ecological importance."
A fully functional, hypercompact CRISPR enzyme, called Cas-Φ, is reported in Science this week. Encoded exclusively in the genomes of huge bacteriophages, Cas-Φ is about half the size of Cas9 and Cas12a. In the study, investigators from the University of California, Berkeley, demonstrate a fully functional CRISPR-Cas-Φ system that uses a single active site for both CRISPR RNA processing and cleaving foreign nucleic acid. Further, the system is active in vitro and in human and plant cells with expanded target recognition capabilities relative to other CRISPR-Cas proteins. GenomeWeb has more on this, here.