Corals can breed themselves out of a one-way trip to extinction

October 22nd, 2008 - 12:28 pm ICT by ANI  

Washington, Oct 22 (ANI): A new research has suggested that faced with a dire shortage of mates of their own kind, corals may be able to cross-breed with certain other coral species to breed themselves out of a one-way trip to extinction.

This finding, released by scientists at the ARC Centre of Excellence for Coral Reef Studies, has raised hopes for the ability of the worlds corals to withstand the rigors of changing climates and human impacts.

According to lead author Zoe Richards, coral reefs worldwide face a variety of marine and land-based threats and hundreds of corals are now on the red list of threatened species.

It is often assumed that rare coral species face higher risks of extinction than common species because they have very small effective population sizes, which implies that they may have limited genetic diversity and high levels of inbreeding and therefore be unable to adapt to changing conditions, she said.

When we studied some particularly rare species of Acropora (staghorn corals), which you might expect to be highly vulnerable to extinction, we found some of them were actually hybrids in other words they had cross-bred with other Acropora species. This breaks all the traditional rules about what a species is, she added.

By hybridising with other species, these rare corals draw on genetic variation in other species, increasing their own potential to adapt to changing conditions.

At this stage how it came about and who the breeding partners are isnt entirely clear, but what is evident is that rare corals previously thought vulnerable to extinction may have more ability to adapt than initially expected, explained Zoe.

Acropora are the main reef-builders throughout the Indian and Pacific Oceans, and so of critical importance to the ability of reefs to cope with changing conditions.

However, till now, very few clear cut examples of hybridisiation were known, and some people did not even accept that corals can cross-breed.

The common Acropora corals occur mainly on reef crests, flats and slopes, whereas several of the rare species occupy more marginal habitats, such as the deeper or extremely shallow water zones where the common species do not grow.

According to Zoe, When we looked at the genetic history of rare corals, we found that they exhibited unexpected patterns of genetic diversity.

This suggests that, rather than being the dying remnants of once-common species, they may actually be coral pioneers pushing into new environments and developing new traits by virtue of the interbreeding that has enabled them to survive there, she added. (ANI)

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