Evolution on Tasmainian Devils
Evolution of Tasmanian Devils
The world's largest surviving carnivorous marsupial, the Tasmanian devil has a thick-set, squat build, with a relatively large, broad head and short, thick tail. The fur is wholly black, but white markings often occur on the rump and chest. Body size also varies greatly, depending on the diet and habitat. Adult males are usually larger than adult females.
Devils once occurred on mainland Australia, but have been confined to Tasmania since pre-European times. The survival of Tasmanian Devils is threatened by Devil Facial Tumour Disease (DFTD), and the species is now listed as Endangered. Devil facial tumour disease emerged in 1996 and causes tumours around in and around the mouth, face and neck and sometimes other parts of the Devils. The disease develops rapidly and is fatal: affected animals die within six months of the lesions first appearing. DFTD is contagious - the cancer cells are spread by biting during feeding and mating. It has spread across approximately 60% of Tasmania and has caused a rapid decline in wild Devil populations.
Characteristics of Tasmanian devil cells have fourteen chromosomes, while the oldest-known strain of the tumour cells contains thirteen chromosomes, nine of which are recognizable and four of which are mutated. More recently-evolved strains have an additional mutant marker chromosome, for a total of fourteen chromosomes. The karyotype anomalies of DFTD cells are similar to those of cancer cells from canine transmissible venereal tumour (CTVT), a cancer of dogs that is transmitted between canines by physical contact.
DFTD cells are not only genetically identical to each other, but also genetically distinct from their hosts, and from all known Tasmanian devils. The cancer originated in a single female individual and spread, rather than arising separately within each individual. Later the devil developed tumours from lesions caused by infected devil’s bites, confirming that the disease is spread
The world's largest surviving carnivorous marsupial, the Tasmanian devil has a thick-set, squat build, with a relatively large, broad head and short, thick tail. The fur is wholly black, but white markings often occur on the rump and chest. Body size also varies greatly, depending on the diet and habitat. Adult males are usually larger than adult females.
Devils once occurred on mainland Australia, but have been confined to Tasmania since pre-European times. The survival of Tasmanian Devils is threatened by Devil Facial Tumour Disease (DFTD), and the species is now listed as Endangered. Devil facial tumour disease emerged in 1996 and causes tumours around in and around the mouth, face and neck and sometimes other parts of the Devils. The disease develops rapidly and is fatal: affected animals die within six months of the lesions first appearing. DFTD is contagious - the cancer cells are spread by biting during feeding and mating. It has spread across approximately 60% of Tasmania and has caused a rapid decline in wild Devil populations.
Characteristics of Tasmanian devil cells have fourteen chromosomes, while the oldest-known strain of the tumour cells contains thirteen chromosomes, nine of which are recognizable and four of which are mutated. More recently-evolved strains have an additional mutant marker chromosome, for a total of fourteen chromosomes. The karyotype anomalies of DFTD cells are similar to those of cancer cells from canine transmissible venereal tumour (CTVT), a cancer of dogs that is transmitted between canines by physical contact.
DFTD cells are not only genetically identical to each other, but also genetically distinct from their hosts, and from all known Tasmanian devils. The cancer originated in a single female individual and spread, rather than arising separately within each individual. Later the devil developed tumours from lesions caused by infected devil’s bites, confirming that the disease is spread