February 17, 2012
Devil’s Contagious Cancer Genome Sequenced
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The Tasmanian devil population is threatened to extinction with a highly contagious cancer. In order to understand the origins of the cancer, researchers have sequenced the complete genome of the cell and traced it back to what they are calling an ℠immortal´ female.Researchers hope by sequencing the genome they can find a way to help the Tasmanian devil. According to Elizabeth Murchison, a Tasmanian native working at the Wellcome Trust Sanger Institute in the UK, “There are targeted drugs that work against cancer genes. We hope some of the mutations that we have found in genes in the devil cancer may point to therapeutic strategies.”
The deadly facial cancer is causing a decline in population of the Tasmanian devil and threatens the species with extinction. The cancer is spread from devil to devil through bites that transfer the living cancer cells, and they bite each other often.
The cancer was first discovered in a photograph in 1996 and scientists thought it was only a one-off case. But by the 2000´s dozens of devils turned up sick with the cancer and it was clear to Murchison that it was a new infectious disease.
In 2006 researchers discovered that the cells were all one cancer spread as a clone from animal to animal, which was a surprise because cancer does not usually travel from individual to individual. Typically the immune system would suppress any foreign cells coming into the body, dying off in the new host.
But the researchers hope to find the answers to their questions through the sequenced genome. Michael Stratton senior author of the paper said, “The cancer genome has evolved as it has spread through the population, but overall it appears to be rather stable. The genetic differences between 104 Tasmanian devil tumors from all around the island present us with a remarkably clear picture of how the cancer has spread in time and space over the last couple of decades, which may help with strategies for disease containment.”
Through gene sequencing, the researchers have discovered more than 17,000 mutations of the cancer cells, which is comparable to the number of mutations in human cancer cells. The scientists now want to know which mutations are most important to help explain the cancer´s evasion of the immune system.
The paper, Genome Sequencing and Analysis of the Tasmanian Devil and Its Transmissible Cancer, was published in the journal Cell and funding was provided by the Wellcome Trust Sanger Institute.
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