TY - JOUR T1 - Adaptive pathways of coral populations on the Great Barrier Reef JF - bioRxiv DO - 10.1101/114173 SP - 114173 AU - Mikhail V. Matz AU - Eric A. Treml AU - Galina V. Aglyamova AU - Madeleine J. H. van Oppen AU - Line K. Bay Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/03/30/114173.abstract N2 - Reef-building corals are extremely important for maintenance of marine biodiversity and coastal economy and are currently under severe threat from anthropogenic warming. Warming is predicted to drive preferential survival of warm-adapted genotypes that have migrated to cooler locations and result in an overall decline in genetic diversity due to bleaching-related mortality. To quantify these trends, we analyzed five populations of a common coral Acropora millepora along the latitudinal extent of the Great Barrier Reef (GBR). Population genomic analysis revealed that most populations were demographically distinct and that migration was indeed preferential southward, from lower (warmer) to higher (cooler) latitudes. However, no recent increase in southward migration was detectable, and inferred migration rates remained closely correlated with predictions of a biophysical model of larval dispersal based on ocean currents. There was also no evidence of recent declines in genetic diversity. A multi-locus adaptation model indicated that standing genetic variation spread across latitudes could be sufficient to fuel continuous adaptation of A. millepora metapopulation to warming over the next 100-200 years. Unexpectedly, we found that naturally low heritability of thermal tolerance in reef-building corals due to contribution from horizontally transmitted algal symbionts would facilitate longer metpopulation persistence. Still, despite good prospects for gradual adaptation, our model predicted increase in severity of mortality events due to random thermal anomalies, which could lead to much faster coral extinction if there are ecological feedbacks preventing rapid reef recovery. ER -