By sequencing the genome of canine transmissible venereal cancer (CTVT) researchers Wellcome Trust Sanger Institute have identified the oldest known living cancer. This cancer arose in a single dog and has survived ever since. By decoding this rare cancer and identifying a certain type of mutation could be used as a ‘molecular clock’ to give an origin of 11,000 years ago. Previous studies have estimated that CTVT is between 200 and 70,000 years old, providing a date of origin much older than originally thought.
In addition to the age of the cancer the phenotype of the founder animal was also investigated. Previous analyses were not able to distinguish between a wolf or an ancient-breed dog origin but by comparing genotypes it was indicated that the animal was likely to have been a dog closely clustered with Alaskan malamutes and huskies. This animal was likely to have had a dark coat and be of medium-large size. It also carried alleles which have been linked to dog domestication.
If you’re interested in other aspects of domestic dog’s evolution head over to my ‘Skull of the Month’ page!