Stress tolerance in corals can be mapped

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Stress tolerance in corals can be mapped

May 30, 2016 - 14:28
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Unique sections of coral DNA can indicate a higher tolerance to environmental stress.

Researchers have discovered genetic markers in the reef-building coral Acropora millepora that provides information about its level of environmental stress tolerance.

Antioxidant capacity is a critical component of stress tolerance because in a range of organisms, including corals, stressors such as high water temperature, poor water quality and even pathogen infection, produce an increase in damaging, highly reactive oxygen molecules (free radicals) inside the tissues.

The ability to tolerate environmental stress varies between individuals, so the team associated with the Australian Institute of Marine Science 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 and also simulated bleaching conditions in the laboratory by exposing corals to high water temperatures.

The genomes of both the wild and laboratory corals were analysed for unique sections of DNA, that correspond with tolerance to the free radicals produced from environmental stress.

Markers identified

As a result two markers were identified that account for differences in environmental stress tolerance and antioxidant capacity. One of the genetic markers that was unveiled accounted for an impressive ~30% of the variation observed in the colonies' ability to deal with the free radicals.

"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," said Professor van Oppen, one of the study's lead authors.

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