Dispersal allows species to persist globally despite local extinctions by tracking environmental conditions. Reef-building corals are declining worldwide, largely attributable to global warming. Climate models indicate that existing coral habitats will continue to deteriorate, suggesting that dispersal to higher-latitude reefs might allow escape from poor conditions. However, the question remains if corals possess enough dispersal potential to escape, and can they evolve to increase their dispersal capabilities? We hypothesize that coral dispersal potential is a heritable, and therefore evolvable, trait associated with specific larval energetic profiles, including lipid and protein metabolism rates reflected in differential expression of metabolic genes. Our research quantifies the genetic variation in these processes and investigates the underlying molecular mechanisms that may be the targets of natural selection under climate change. Establishing the extent to which corals might be able to avoid the adverse effects of climate change through range shifts will enable improved predictions of coral persistence and add to our basic understanding of adaptive evolution in the sea.
The project provides broad opportunities for public outreach and education. Coral biology is enticing for undergraduate volunteers and the co-PI has mentored twenty-five undergraduates from diverse backgrounds. Students learn how to use genetics and bioinformatics to answer questions of ecology and evolution. This research also involves students from James Cook University in Australia. Public dissemination of science is also extensive ranging from public lectures at ?Science Under the Stars? series to participating in Woman in Science events.
Coral reefs worldwide are in decline and are severely threatened by the effects of climate change. The survival of corals into the future critically depends on their ability to handle the effects of global warming. While the adult coral cannot move, their larvae disperse long distances and therefore could, in principle, ensure the survival of the species by colonizing new locations that are cooler than their home reefs. The results of our project elucidate, for the first time, the molecular genetic mechanisms underlying the potential of coral larvae to colonize new habitats. We demonstrate significant effects of genetic background on early responsiveness to settlement cue and on red fluorescence, both of which indicate dispersal potential. Gene expression associated with higher settlement included up-regulation of receptor activity and cell surface/extracellular matrix components, which is intuitive given that the coral larvae perceives its environment through extracellular matrix. Expression patterns that predicted red fluorescence suggested that redder larvae grew less, developed slower, and exhibited differential regulation of stress response genes, suggesting that redder larvae may be more dispersive or may just be more stressed. Overall, we found strong genetic effects on gene expression. The strongest of these were observed for genes implicated in genome stability and stress response, indicating genetic variation in coral’s ability to handle stress. The heritable variation observed in our study can serve as raw material for natural selection, providing hope that corals will be able to evolve in response to climate change. This project involved two undergraduate students, one of whom was a female minority and the other was with the Freshman Research Initiative (FRI) at the UT College of Natural Sciences. The results were presented at two scientific conferences and at two public outreach events, including Breakthrough Austin, which caters to students who will be the first in their families to go to college.
