A University of Hawaii researcher has confirmed corals have some of the same genes as humans, a finding that could help scientists understand those animals that are key to marine diversity.
Alexander Stokes discovered the genes in humans that are involved with ion channels — proteins that form holes in cell membranes to allow cells to respond to external stimuli such as heat, cold or acidity — also exist in corals.
The findings were part of the world’s most comprehensive analysis of coral genes, published last week in the journal eLife, according to the University of Hawaii John A. Burns School of Medicine.
An international research team studied the coral gene database to learn more about corals and how they evolved and adapted to changes in the environment. Corals are important because they shelter 25 percent of marine life and protect shoreline communities, despite covering less than a tenth of 1 percent of the ocean floor.
The study also comes months after scientists with the National Oceanic and Atmospheric Administration warned that the world was experiencing the longest global coral die-off ever recorded.
Global coral bleaching prompted the die-off and happens when corals stressed by environmental changes such as rising temperatures expel the algae that live in their tissue, leaving corals white, weaker and susceptible to death.
The international die-off hit Hawaii late last year, but most of Hawaii’s coral recovered.
Ruth Gates, director of the University of Hawaii’s Hawaii Institute of Marine Biology, collaborated on the Rutgers University-led study and brought Stokes into the project because of his expertise with ion channels as an assistant professor of cell and molecular biology at the UH Laboratory of Experimental Medicine.
An ion is a positively or negatively charged chemical. Salt, for instance, is made up of the positive ion sodium and the negative ion chloride. Sodium plays a key role in nerve communication, much like electrons flowing through a wire.
Stokes said ion channels help cells sense the environment and respond to stimuli. The ion channels found in the corals sense temperature and acidity.
He said the existence of ion channels was suspected in corals but hadn’t been found before by locating the genes in coral DNA.
“It tells us a lot more about how coral works,” he said. “It’s not such an enormous mystery.”
Researchers still don’t know how corals make use of the ion-channel information — they can’t move to avoid stimuli, but the large amount of literature on ion channels in humans can be applied to corals. And any discoveries in how the ancestral proteins in corals work could shed light on human systems as well, Stokes said.
“We’re not so far from these corals,” he said. “We’re closer to nature than we think.”
Stokes said he has already started work on understanding how corals use ion channels, and could use the knowledge about them from studies in humans, which has led to the creation of chemicals that can open and close ion channels.
One way to study the ion channels in coral is to isolate coral cells and load the cells with a dye sensitive to an element such as calcium, then taking rapid photographs to monitor any changes when the environment is altered, which will tell whether calcium was allowed into the cell through the ion channel.
Stokes found the ion channels in corals by comparing genomes, which contain all the genes of a species, of 20 different coral species with the human genome.
In humans some ion channels help individuals react to the environment, such as heat or cold outside our bodies, while others are local to a cell, such as adjusting the acid in our stomachs.
“Human medicine shows us that corals are not so different, and we all respond to the environmental side of things,” he said, but added that there is a slight difference. “It’s the difference between cellular sensing and your brain sensing. The corals don’t have brains, so they’re really just responding.”
