I always wondered if something like this happened to wooly mammoths. It would be considered natural selection wouldn't it? _________________________________________________ Tasmanian Devil falling prey to cancer SYDNEY (Reuters) - A lack of genetic diversity in Australia's Tasmanian Devil means it has failed to launch an immune defense response to a facial cancer decimating populations, Australian researchers say. The facial cancer produces large tumors on the face and neck of the Tasmanian Devil, found only on the southern Australian island state of Tasmania, which interfere with feeding. Death usually occurs within six months. The Tasmanian Devil is a carnivorous marsupial about the size of a small muscular dog. It has black fur, gives off a skunk-like odor when stressed, and earns its name for its ferocious temperament and disturbing call. "We found that the Devils do not mount an immune response against the tumor," said Katherine Belov from Sydney University's School of Veterinary Science. "Essentially, there are no natural barriers to the spread of the disease, so affected individuals must be removed from populations to stop disease transmission," said Belov. "Loss of genetic diversity in these genes just opens the door for emergence and rapid spread of new and old disease," Belov said in a statement on the Tasmanian Devil research. The study also found that the facial cancer was genetically identical in every animal and had originated from a single contagious cell line, spread throughout the population by biting during fights for food and mates. The Tasmanian Devil faces extinction in 10 to 20 years due to the facial cancer, the report said. The research by Sydney University, the University of Tasmania, the Australian Museum and the Tasmanian government was published online by the Proceedings of the National Academy of Sciences of the United States of America.
Genetic failure and extinction are the mechanisms for natural selection. Natural selection has to do with the survivors.
"Environ"mentalists get really emotional about their favorite animals. Even if they are vicious killers.
Their lack of genetic diversity is due to the low population numbers, which in turn is due to human activities reducing those numbers. Certainly we can ethically work to save the species.
If they are only on one island, how many of them could there be to start with?? And I can't imagine us eating them. How did they get cancer to start with? Did it jump over from an animal humans brought to the island?
Even if a species can maintain a small population due to habitat loss, global warming, hunting, and other factors, once the gene pool is reduced enough, something like this can take over and deliver the last blow that leads to extinction.
ummm, yes. But I don't know how varied the gene pool is. Maybe this is the result of too much inbreeding.
Well.what ive heard is that all of evolution is actually caused from viral infections. That is the theory at elast on my half of the world. Because there is such stagnated growth in the sceme of things of the past events, I believe that it would have to deal with a constant fluctuation within the genomes of the individual species. Imagine that...the constant balance between life is between the micro level and the macro not some random events that might or might not take place in history. Ya know, the crashing of the asteroid. What if it was a plague that took place...that makes more sense than cancer.
Cancer is not contagious, as far as I know. Cancer is a result of genetic errors accumulating over a number of cell generations, leading to the uncontrolled cell-division. Its likelihood can be increased by different chemicals and other environmental factors, as well as by inbreeding, which can cause cellular mechanisms that normally work to prevent cancer to fail. (Didn't really look anything up, just put a small description together, anyone feel free to expand or correct me.)
When did the Cancer became contagious? Next thing you know, it will jump to humans and like flu, spread everywhere!!!
WoooHoooo!! Go Cedric Go Cedric Hope of Cure The unlikely would-be saviour of the world's largest marsupial carnivore is an unassuming devil named Cedric. In a development described as "the most exciting" in the five-year quest to halt devil facial tumour disease (DFTD), Cedric has shown an immune response to the unique communicable cancer. He is the first of his species known to do so, and University of Tasmania researchers expect he will remain disease free, despite being exposed to DFTD. This would mean that devils sharing Cedric's mix of immune-related genes may be resistant to DFTD, or capable of responding to a vaccine. And that would save the endangered species from its march toward extinction, which had appeared unstoppable. DFTD has wiped out an estimated 53 per cent of the species in the past 12 years. "I think this is the most exciting thing that has happened in this program - the devils could be their own saviours," said Greg Woods, who is conducting the research for the Save the Tasmanian Devil program, with PhD student Alex Kreiss....
Damn right we do. "Natural" doesn't mean "desirable". This cancer is a particularly odd one. In ways, it's actually more like a parasite than a cancer. In general, cancer is not contagious. Some cancer can be caused by viruses which are contagious. For example, cervical cancer is not contagious but it is strongly related to a past HPV infection, and HPV is contagious. The "cervical cancer vaccine" is actually a vaccine for the two most common strains of HPV. Having the vaccine won't prevent cervical cancer if you have already had a HPV infection. But that's not the case here - this is far stranger, and much creepier! This cancer presumably originated with a cell mutation in an individual devil. That cell divided and multiplied into a facial tumor. That devil had a fight with another devil (this happens a lot). In the process, a bit of the tumour (maybe just a few cells) ended up in a cut on the other devil's face. By rights, that should have been the end of it - those cells should have been abolished with prejudice by the other devil's immune system, just like rejecting an organ transplant from an incompatible donor. But no! The cells continued to divide and multiply. The second devil's body did not reject them, so the tumour kept growing... now on two devils instead of one. That single tumour has been growing ever since, attached to more and more devils. It's like an involuntary organ transplant, or a parasite. The tumor on any given devil was never really part of that devil (the original host is presumably long dead) - it is an external entity that implanted itself into the poor devil's face. Freaky! I don't know if there's something unique about the devil's immune system that prevents the foreign tissue from being rejected, or if it's something unique about that particular cancer. In any case, it's not a general thing - foreign tissue (cancerous or not) is almost always destroyed by an animal's immune system. Edit - reading the articles linked above, it's been suggested that the devil population is so inbred that they are essentially all pretty good transplant matches for each other.
I've just found that this cancer is not unique - there is a similar but non-fatal cancer in dogs that seems to have been around for maybe two hundred years. Contagious Cancer In Dogs Confirmed; Origins Traced To Wolves Centuries Ago (MedicalNewsToday.com - August 2006)
Also there is Feline Acquired Leukemia, but that is a retro virus along the lines of HIV, iirc. And of course Human Papliloma virus (spelling?) that is a primary cause of cervical cancer.
