A process that changes the regulation of genes could help corals acclimatize to the impacts of global warming.

Cells commonly control gene expression by adding a methyl group to part of the DNA, changing how the information on the DNA is read without changing its genetic code. Researchers at KAUST wanted to investigate whether DNA methylation could play a role in helping corals adapt to climate change.

They placed colonies of the smooth cauliflower coral, Stylophora pistillata, in seawater aquariums with varying acidity levels for two years. Ocean acidification is a consequence of climate change and hinders the ability of corals to produce the calcium carbonate skeleton they need to maintain their structures. The researchers hypothesized that DNA methylation might allow corals to mitigate these effects by changing the way they grow.

After two years, the team sequenced the genomes of the corals and determined changes in methylation patterns.

"We noticed that corals grown under more acidic conditions had higher levels of DNA methylation," says geneticist Yi Jin Liew. "Genes with increased methylation were related to cell growth and stress response, but not to calcification as we initially proposed," he says.

In line with this finding, the team discovered that cell and polyp sizes in the corals also increased with rising acidity. "The coral polyps sit in little cavities called calyxes in which they can retreat for protection," explains molecular biologist Manuel Aranda. Larger polyps have larger calyxes.

"If the calyx is bigger, the coral needs to produce less skeleton to grow at the same pace. I call this the 'Swiss cheese hypothesis,' where the coral makes bigger holes so it needs to make less cheese, which allows it to grow at the same speed even though skeletal production is impaired."

This trait would be advantageous in an environment where competition for space and light is an important selective pressure.

The findings indicate that DNA methylation can be used as a marker of coral stress. This epigenetic mechanism might also be harnessed to grow corals under future ocean conditions to prime them for increased temperatures before placing them on reefs, says Aranda. This process is known as environmental hardening.

"We hope our contribution will change the current perception among reef biologists that epigenetics do not contribute much to coral resilience," says Liew.

The team next plans to investigate whether these epigenetic changes can be passed down to future generations. "The idea is fairly revolutionary," says Liew.

Research paper

Related Links
King Abdullah University of Science and Technology
Water News - Science, Technology and Politics

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

World's largest freshwater pearl goes for 320,000 euros
The Hague (AFP) May 31, 2018
The world's largest known freshwater pearl, which once belonged to Catherine the Great, was sold Thursday in the Netherlands for 320,000 euros ($374,000), auction house Venduehuis said. Known as the Sleeping Lion pearl due to its distinctive shape, the pearl was likely formed in the first half of the 18th century in Chinese waters, possibly even the Pearl River. The auctioneers said the jewel weighs some 120 grams (around 4.2 ounces) and is almost seven centimetres (about 2.7 inches) long making ... read more