Coral study reveals the genomics of local adaptation

AUSTIN, Texas, Nov. 7 (UPI) -- For the first time, scientists have measured the genomic divergence that occurs as two populations of the same species adapt to two different environments.

Researchers at the University of Texas observed the phenomenon among populations of mustard hill coral, Porites astreoides, common in the Florida Keys.

Scientists were able coax genomic tinkering by moving coral samples from their home to a new site. Experiments revealed samples from coral populations living closer to shore made more genomic changes than samples of the same species collected from populations farther from the coast.

Coral living in shallower coastal waters are more likely to face shifting environmental conditions. As the new research shows, these coral populations are better able to adapt to new environs.

"It is exciting that populations so close together -- these reefs are less than 5 miles apart -- can be so different," Carly Kenkel, now working at the Australian Institute of Marine Science, said in a news release. "We've discovered another way that corals can enhance their temperature tolerance, which may be important in determining their response to climate change."

An organism's genome is made up of the genes it turns on or expresses. Scientists have previously measured differences in the amount of specific genes expressed by two divergent populations of the same species, but the latest research -- detailed in the journal Nature Ecology and Evolution -- proves separate populations of the same species can turn different genes on and off.

This genetic flexibility enabled closer-to-shore coral to not only better adapt to new environs, but also withstand environmental stressors. Samples from more adaptive coastal coral populations were more likely to survive induced bleaching than samples from farther ashore.

Researchers credit their revelations to a more wide-angle approach.

"We saw different capacity for gene expression plasticity between coral populations because we looked at the behavior of all genes taken together instead of focusing on individual genes," concluded Kenkel. "If we hadn't, we would have missed the reef for the coral, so to speak."