Selective breeding can produce heat tolerant corals

Platygyra coral colony spawning bundles of eggs and sperm in the water column. Credit: Anna Scott

Coral populations have the genetic potential to adapt to warming oceans, according to new research from researchers at Southern Cross University.

“Our previous work revealed that corals in an extreme environment have an exceptionally high heat tolerance, in part due to the genetic adaptation of the coral animal,” said Dr Emily Howells, senior researcher at the National Marine Science Center at Southern Cross University. .

“In this study, we wanted to test whether we could transfer these beneficial genetic variants to a population of relatively heat-sensitive corals living in milder ocean conditions.”

The study, led by Dr Howells and also involving Professor David Abrego of Southern Cross University, was an international collaboration between New York University Abu Dhabi, Oregon State University, the King Abdullah University of Science and Technology, Zayed University, CSIRO and the University of Wollongong.

The researchers crossed corals from the thermally extreme Persian Gulf with those of the same species from the milder Indian Ocean and measured the performance of many families of their offspring.

The team found that heat tolerance increased by up to 84% when Indian Ocean dams were mated with Persian Gulf sires and was, on average, equivalent to offspring heat tolerance with both parents from the Persian Gulf.

“It was an impressive result, because while we expected to see some improvement in heat tolerance, the signal was much stronger than expected from the genetic contribution of single fathers, as maternal effects also contribute to the tolerance of the offspring, “said Dr Howells. .

Genome-wide sequencing of coral families confirmed these results by revealing that genetic variants positively associated with heat survival were primarily inherited from relatives in the Persian Gulf.

The researchers also deployed the offspring to the Indian Ocean site and found that the corals crossed with the Persian Gulf fathers survived as well as the purebred corals from the Indian Ocean, but both had longer survival. higher than the non-native Persian Gulf race corals.

These results demonstrate that corals can be selectively bred for better heat tolerance using corals from populations living in extreme or warmer environments that have a higher proportion of heat-tolerant genetic variants due to local adaptation.

Selective breeding has the potential to be used to improve the resilience of targeted coral populations to global warming, but requires additional testing before it can be implemented in response and restoration programs,” said the Dr Howells.

“However, the most important actions to improve the resilience of all coral populations are those that limit the extent of climate change.”

An unexpected finding from the study was that genetic variation was not limited to the Persian Gulf and was also present at low levels in the cooler populations of the Indian Ocean.

“One of the most exciting results of the study was that a small number of Indian Ocean sires produced offspring with surprisingly high heat tolerance, and these sires had some of the same genetic variants associated with the heat tolerance that prevailed in the Persian Gulf, ”says Dr. Howells.

“Such permanent genetic variation is essential for natural selection to occur in warming environments. “

Co-author Dr David Abrego said ongoing international collaborations are critical to this work.

“This study has fostered more international collaborations as we investigate whether these heat-tolerant variants occur in other regions of the Indo-Pacific,” said Dr. Abrego.

Dr Emily Howells’ current research is studying permanent genetic variation for heat tolerance in Australian coral populations with support from the Hermon Slade Foundation and under the Reef Restoration and Adaptation Program, a partnership of the Australian government to help the Great Barrier Reef to resist, adapt and recover from the impacts of climate change.

“Our study, along with other recent research, indicates that some coral populations exhibit greater genetic variation for heat tolerance than previously thought,” said Dr Howells.

“Now, on the Great Barrier Reef, we are undertaking in-depth assessments of the physiological and genetic variation that exists within and among breeding populations as well as between them. The objectives of this research are to develop diagnostic markers of tolerance. heat in corals and improve understanding of the potential for adaptation to climate change.

Protect coral reefs more effectively from climate change

More information:
Emily J. Howells et al, Improving the heat tolerance of reef-building corals to future warming, Scientists progress (2021). DOI: 10.1126 / sciadv.abg6070

Provided by Southern Cross University

Quote: Selective breeding can produce heat tolerant corals (2021, August 24) retrieved September 30, 2021 from

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Jeanetta J. Stewart

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