You probably think that corals are very simple animals who also have a very simple genome. According to an international team of researchers from Australia, Germany and Japan, this is not true and corals might be more complex than us. They say that corals have as many as 20 or 25,000 genes, a number very similar to humans. And corals share a great number of genes with other vertebrates which govern their nervous and immune systems. The researchers also say that corals are using their innate immune systems to fight pandemics the same way as we do. Fascinating study…
As an example of the various pandemics which affect the corals, below is a photo of a typical coral disease. (Credit: Bette Willis for CoECRS) Here are two links to a larger version and to a photo gallery showing other diseases.
Here are some comments from Professor David Miller who works on Evolutionary genetics at the Australian Research Council Centre of Excellence for Coral Reef Studies (CoECRS).
"We actually have quite a lot in common with corals, though it might not appear so," Professor Miller says. "For example, we have been amazed at how many of the genes involved in innate immunity in man are present in coral — and just how similar they are."
As very few of us know, corals are currently facing a number of pandemics named 'black band,' 'white plague,' 'white pox,' or 'white syndrome.' How do they fight these diseases?
"The coral immune system is a black box at present. How corals cope with the worldwide upsurge in diseases, and the extent to which they are affected by other stresses caused by human activity are important questions. The similarity of the coral and human innate immune repertoires implies that they may function in similar ways, so the hope is that we can apply what we know about human health to better understand coral disease," adds Miller.
This work on the coral genome has involved other researchers in Germany and Japan, but also Dr. Eldon Ball of the Molecular Genetics & Evolution group at the Australian National University.
They've published their results in Genome Biology under the name "The innate immune repertoire in Cnidaria - ancestral complexity and stochastic gene loss" (Volume 8, Issue 4, Article R59, April 16, 2007). Here are two links to the abstract and to the full paper (PDF format, 34 pages, 643 KB).
Finally, Miller says that "by exploring the ancestral immune genetic repertoire of corals and how it functions in a simple animal, we will gain new insights which will help in the battle against human disease." After all, corals appeared more than 200 million years ago — slightly more than us. They probably learned something we don't know yet.
Sources: ARC Centre of Excellence for Coral Reef Studies, April 25, 2007; and various websites
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