Tasmanian Devil Salem died at age seven but made a difference to her endangered species. Only 50 micrograms of her tissue was taken and processed by Australian genetic scientist Elizabeth Murchison, using new US technology, to produce the first devil genome sequence. As a result, the fight against devil facial tumor disease now has a draft DNA reference map. This was presented at a genetic conference in Hobart yesterday.
Dr Murchison, of the Sanger Institute in Cambridge, England said, “This is really a prerequisite for understanding the genetics of this cancer…We now have a usable reference genome so we can look at its mutations.” The facial tumor is believed to have arisen as a mutation in an individual devil about 20 years ago. Then this always fatal cancer spread to more than three-quarters of the devils' range in Tasmania. In five years it could cover the whole range, according to Menna Jones, scientific adviser to the state government's Save the Tasmanian Devil program. She said at a public meeting in Hobart, “We only have about 30,000 individuals left to run this race.”
Now with the genome sequenced, Dr Murchison said, devil researchers could follow the geographic travels of the cancer. She said, “By comparing our draft sequence with samples taken from many hundreds of devils suffering from this cancer, we can begin to look at the spread of the disease quite literally…We will be able to identify any variants and mutations as it has moved through the population of devils.”
At present under a national conservation program, dozens of devils are being bred by zoos. Isolation of healthy devils is the only hope. Dr Murchison said that by identifying mutations it might also be possible one day to treat the disease with drugs. The reference genome was sequenced in eight days using a machine developed by Californian company Illumina. Dr Murchison was working with the Cancer Genome Project at the UK's Wellcome Trust Sanger Institute.
Sanger Institute director and Cancer Genome Project joint head Mike Stratton said the sequence was more than a boon to efforts to protect the devil. “We believe this research will also teach us important lessons about the evolution of cancers…We are actually peering into the very same cancer that originated in just one devil some 20 years ago, a cancer that has long survived its original host…In research terms this is truly unique. It will provide an unprecedented window into the evolution of cancer,” he said.