Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Adaptive selection and rapid divergence since the last glacial maximum in heat tolerant corals from Western Australia (#65)

Jia Zhang 1 2 3 , Zoe Richards 4 5 , Arne A. S. Adam 4 , Cheong Xin Chan 6 , Chuya Shinzato 7 , James Gilmour 8 , Luke Thomas 8 9 , Jan M Strugnell 10 11 , David Miller 1 2 3 , Ira Cooke 1 3
  1. Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, QLD, Australia
  2. ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QDL, Australia
  3. Department of Molecular and Cell Biology, James Cook University, Townsville, QLD, Australia
  4. Coral Conservation and Research Group, Trace and Environmental DNA Laboratory, School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia
  5. Western Australian Museum, Welshpool, WA, Australia
  6. School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia
  7. Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
  8. Indian Oceans Marine Research Centre, Australia Institute of Marine Science, Crawley, WA, Australia
  9. Oceans Graduate School, The UWA Oceans Institute, The University of Western Australia, Perth, QLD, Australia
  10. Department of Marine Biology and Aquaculture, James Cook University, Townsville, QLD, Australia
  11. Centre for Sustainable Fisheries and Aquaculture, James Cook University, Townsville, QLD, Australia

Climate change threatens the survival of coral reefs globally, primarily through mass bleaching and mortality as a result of marine heatwave events. While these short-term effects are clear, predicting the fate of coral reefs over the coming century is a major challenge. One way to understand the longer-term effects of rapid climate change is to examine the response of coral populations to past climate shifts. Coastal and shallow-water marine ecosystems such as coral reefs have been reshaped many times by sea-level changes during the Pleistocene, yet, few studies have been able to directly link this with its consequences on population demographics, dispersal, and adaptation. Here we use whole-genome sequencing data to explore such links for the reef-building coral, Acropora digitifera, in northwestern Australia. We identify three genetically distinct populations and show that their rapid divergence since the last glacial maximum (LGM) is likely driven by founder-effects. Signatures of recent selective sweeps are present in all three populations with different patterns of functional enrichment between inshore and offshore habitats. However, the photosymbiont communities are largely undifferentiated between all three locations indicating that selection on host genes has been the primary driver of adaptation for this species in northwestern Australia.