AsianScientist (May 16, 2016) – Researchers in Australia have revealed that unique sections of coral DNA can indicate a higher tolerance to environmental stress. The findings, published in Science Advances, could act as a guide for novel reef restoration and management programs including selective breeding for corals and assisted migration to boost populations of more stress-tolerant corals.
Studies have shown that stressors such as high water temperature, poor water quality and even pathogen infection can produce an increase in damaging, highly reactive oxygen molecules (free radicals) inside the tissues of corals and other organisms. But the ability to tolerate environmental stress varies between individuals, so the team set out to find the most stress-tolerant of the common reef-building coral Acropora millepora.
The team took coral tissue samples from reef sites along the Great Barrier Reef that were experiencing bleaching, where microalgae living within coral polyps die off, leaving the tissues white. They also simulated bleaching conditions in the laboratory by exposing corals to high water temperatures.
The genomes of both the wild and laboratory corals were analyzed for environmental stress biomarkers, unique sections of DNA that correspond with tolerance to the free radicals produced from environmental stress. One of the genetic markers identified actually accounted for an significant ~30 percent of the variation observed in the colonies’ ability to deal with the free radicals.
“Corals that have a better capacity to deal with environmental stress can be identified from their individual genetic makeup,” said Professor Madeleine van Oppen from the University of Melbourne and the Australian Institute of Marine Science.
“The genetic markers we identified can be easily used to create fine-scale distribution maps of coral stress tolerance, which may be informative for designing Marine Protected Areas for coral conservation.”
In the future, van Oppen said, reef managers may consider moving corals from one reef area to another, or to selectively breed more tolerant corals by cross-breeding the most stress-tolerant ones.
“The genetic identification of stress tolerant colonies can guide these processes to ensure the most suitable genotypes are used,” she added.
The article can be found at: Jin et al. (2016) Genetic Markers for Antioxidant Capacity in a Reef-building Coral.
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Source: University of Melbourne; Photo: Shutterstock.
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