A cancer normally lives and dies with a person, however this is not the case with a particular sexually transmitted cancer in dogs. In a study published in the January 24, 2014 issue of Science, a team of researchers led by Professor Sir Mike Stratton (image), Director of the Sanger Institute, has described the genome and evolution of this cancer that has continued living within the dog population for the past 11,000 years. A commentary on these results, written by canine genetics experts Dr. Heidi Parker and Dr. Elaine Ostrander, is also published in the same issue of Science. Scientists have sequenced the genome of the world’s oldest continuously surviving cancer, a transmissible genital cancer that affects dogs. This cancer, which causes grotesque genital tumors in dogs around the world, first arose in a single dog that lived about 11,000 years ago. The cancer survived after the death of this dog by the transfer of its cancer cells to other dogs during mating. The genome of this 11,000-year-old cancer carries about two million mutations – many more mutations than are found in most human cancers, the majority of which have between 1,000 and 5,000 mutations. The team used one type of mutation, known to accumulate steadily over time as a “molecular clock,” to estimate that the cancer first arose 11,000 years ago. “The genome of this remarkable long-lived cancer has demonstrated that, given the right conditions, cancers can continue to survive for more than 10,000 years despite the accumulation of millions of mutations,” says Dr. Elizabeth Murchison, first author of the Science article from the Wellcome Trust Sanger Institute and the University of Cambridge.
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