Gene-editing system could one day aid coral conservation efforts, researchers say
Increasing ocean water temperatures have put the survival of coral reefs at high risk over the past few decades. The recent findings have sparked concern for the survival of these reefs and potential conservation methods.
While there is not yet a solution, scientists can now study the gene functioning of corals, which could potentially help to better understand these fragile ecosystems and aid in conservation efforts.
In a recent study, Stanford scientists and their colleagues used the CRISPR-Cas9 gene-editing system to modify genes in coral.
Acropora millepora coral at the Australian Institute of Marine Science. (Phillip Cleves)
CRISPR is a relatively new technology that allows researchers to make targeted mutations in the genomes of organisms.
They can break the gene function of the gene of interest and then see what happens, according to Phillip Cleves, Ph.D, a postdoctoral scholar at Stanford and author of the study.
The ability for scientist to modify the genes to study gene function traditionally has been only able to be done in a certain subset of organisms, such as fruit flies, mice, yeast and fish, but now modifying gene function can be done on almost any organism that you're interested in, including corals, using CRISPR.
The scientists found definitive evidence that CRISPR could be a potent resource for coral biologists for what appears to be the first time.
"It's a first step," Cleves said. "We hope this technique is an important first step for scientist to begin to understand what genes do in corals."
The study was published online on April 23 in the science journal Proceedings of the National Academy of Sciences.
The research lab has been generally focused on trying to understand the genetic basis of coral symbiosis, according to Cleves.
Corals have a symbiotic relationship with the algae that live inside of their cells. The relationship provides algae with shelter, gives coral reefs their colors and supplies both organisms with nutrients.
That symbiosis relationship is critical for coral survival.
When coral are exposed to increased water temperatures over a period of time, the symbiosis breaks down in the corals, and the corals will lose their algae. That process is called bleaching.
This May 2016 photo provided by NOAA shows bleaching and some dead coral around Jarvis Island, which is part of the U.S. Pacific Remote Marine National Monument. (Bernardo Vargas-Angel/NOAA via AP)
"We've lost about 50 percent of the world's reefs in the past 30 years. We've lost about 30 percent of the Great Barrier Reef," Cleves said. "And so we're really in an important moment to understand what's actually happening."
Extended marine heatwaves are becoming more common with climate change, and this is already having a large impact on reef ecosystems.
"We don't really understand what is going on. We don't really understand the genetic mechanisms for how the corals interact with their algal partners, and why it breaks down upon thermal stress," Cleves said.
The researchers think that understanding what genes are important for that symbiosis and coral bleaching will help in understanding what's going to happen in the future.
It will also help in understanding where to focus conservation efforts, focusing on corals that have the highest probability of survival, according to Cleves.
"Our real focus in the lab is to basically understand what coral genes do," Cleves said.
By studying coral genetics, researchers can better understand if there is certain genetic makeup that makes coral more likely to survive coral bleaching.
"Are there genes variants that could help coral survive? If so, we would want to know what the genes are, and then we could go out and search for natural populations that have the highest chances of survival and protect those," Cleves said.
There are 'winners' and 'losers' among corals as they respond to the accumulating impacts of climate change. (ARC Centre of Excellence for Coral Reef Studies/ Mia Hoogenboom)
There are a number of potential avenues that this research could have on coral reefs, and a number of ways that it could impact conservation methods.
However, the research is still in the early stages and the focus is currently on understanding the basic biology in the lab.
"We are in this phase where we just need to learn. We just want to learn how corals work and the basic biology of corals because we think that that will help us," Cleves said.
The researchers are now interested in understanding what genes are important for skeleton formation in corals as well as what genes are important in coral tolerance to heat.
It is uncertain what the research will lead to in the future, but there are numerous potential impacts.
"This is the first time that we've been able to ask what a gene does in coral, and that's pretty exciting," Cleves said.