By Jean Balchin 02/05/2018

Recent research published in Nature Climate Change has found that reef fish can inherit from their parents the genetic tools to adjust to warming oceans. Obviously, given that our climate is rapidly changing, the decline of animal populations – particularly marine populations – is a distinct concern.

For the first time, researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) and the King Abdullah University of Science & Technology (KAUST) can report new evidence of reef fish adjusting to global warming conditions at the genetic level.

According to senior author Prof Philip Munday of Coral CoE at James Cook University:

“When parents are exposed to an increase in water temperature, we found that their offspring improved their performance in these otherwise stressful conditions by selectively modifying their epigenome.”

What is epigenetic change?

Basically, epigenetic change refers to chemical modifications in the DNA that signals genes to be switched on or off. These subtle changes may be stimulated by a diverse array of factors, including disease, famine, or, as indicated here, heat stress.

The Study:

In this study, the researchers subjected reef fish to elevated water temperatures. It was discovered that when both parent and offspring fish experienced the same elevated water temperatures, responsive changes in their epigenome, via selective DNA methylation, were observed that enhanced the next generation’s ability to cope with the new, warmer temperatures.

Co-author Prof Timothy Ravasi of KAUST explained:

“We reared spiny chromis damselfish, a common Indo-Pacific reef fish, for two generations under three different water temperatures, up to 3 degrees Celsius warmer than current-day ocean temperatures. The next generation appeared to be advantaged by parental exposure to elevated temperatures. The offspring’s altered gene expression, also referred to as ‘acclimation,’ allowed them to maximise oxygen consumption and energy use.”

This acclimation may buffer populations against the impacts of rapid environmental change and provide time for genetic adaptation to catch up over the longer term, according to the researchers.

However, while this study heralds good news of reef fish, we must also keep in mind that the decline of the coral habitat, coupled with pollution and other factors resulting from climate change, remain overriding concerns for their survival.

You can read the paper “The epigenetic landscape of transgenerational acclimation to ocean warming” here.