Corals could have thousands more genes than humans and may have been one of the first animals to develop immune system genes to fight disease, according to new research
Scientists at James Cook University in Townsville have discovered these simple marine animals have a vast and complex genetic repertoire, including many genes already lost from other animals during the process of evolution.
“They’re like a living museum of ancestral animal genes,” molecular biologist and coral genomics expert Professor David Miller said.
The astonishing and unexpected discovery could shed light on the origins of nervous and immune systems in animals as well as providing new insights into curing and controlling human diseases.
“We actually have quite a lot in common with corals, though it might not appear so. 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,” Professor Miller said.
Four years ago, researchers were predicting coral could have about 10,000 genes “but we’ve found almost that many already and clearly have a long way to go yet”. Based on the current rate of gene discovery, corals could have as many as 25,000 genes, compared with the human complement of 20-23,000 genes.
However, corals use their genes to produce only a dozen types of body cells, whereas humans have developed thousands of different cells types.
The research team hopes they can use knowledge about the human immune system to control outbreaks of coral diseases such as black band and white plague that are killing corals on the Great Barrier Reef and other reef systems across the world.
“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,” Professor Miller said.
Corals are thought to have evolved 240 million years ago and about 12 per cent of known coral genes are shared with vertebrates, including “lost genes” for the development of nerves, vision, DNA imprinting, stress responses and immune system genes.
But despite their potential value to medicine and other branches of science, Australia’s corals were largely genetically unexplored, and there was currently no government funding for research to sequence the coral genome, Professor Miller said.”Coral genomics has largely been ignored because of assumptions that they were simple, lower order animals. But now it looks as if they have twice as many genes as many mammals.”
The genomes of several iconic local coral species had already been sequenced by overseas laboratories, and Australia was being left behind in a crucial area of research, he said.
“If important discoveries leading to new technologies are made, we will have to pay to import them.
“Sequencing a coral genome is a real contribution which Australia can make to human knowledge with potential benefit to society, the environment and the economy.”