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Can someone please explain why this is happening only now and why the species isn't already extinct? From the way this article is written, it seems the main cul

Can someone please explain why this is happening only now and why the species isn't already extinct? From the way this article is written, it seems the main culprit is the animals biting each other. However, they must have done this for tens or hundreds of thousands of years. So why are they suddenly getting face cancer? And why is the species threatened by this problem only now? What information are we missing here?

notavalleyman 8y ago
Just speculating here, but there might not be anything temporally "special" about the spread of infection right now. We might find that every N years a new disease emerges, spreads, and then is adapted to - and we're just lucky enough to be around to observe this current wave
- FakeComments 8y ago
  Surely this must be true given all the weird junk in our DNA and specialized traits like the genes that cause sickle cell, but resist malaria. https://www.cdc.gov/malaria/about/biology/index.html https://www.cdc.gov/malaria/about/biology/index.html
  - Nasrudith 8y ago
    That is true but sickle cell isn't the best example for that. It is essentially a 'useful glitch' of a trait as opposed to something viral. There are ancient viruses embedded in human DNA. Effectively the embedding is just another form of mutation to the genome (although there are distinct patterns). It gets embedded regardless if it is copying errors, mutagenic chemicals, or electromagnetic radiation in cause. https://www.nytimes.com/2017/10/04/science/ancient-viruses-dna-genome.html https://www.nytimes.com/2017/10/04/science/ancient-viruses-d... Theoretically it /is/ possible for the right sequence of say radiation damage and auto-repair to give rise to segments of a virus in DNA but the odds are stupidly lower. To use an example technically you could scatter scrabble tiles randomly to get quotes from Shakespeare if you do it enough but you are far more likely to occasionally get gibberish than "WHAT LIGHT THROUGH YONDER WINDOW BREAKS" - let alone in the right order.
    - FakeComments 8y ago
      I’m not sure I follow what you’re saying. Nobody claimed sickle cell had anything to do with viruses; I claimed that sickle cell is a mutation which provides a protection to malaria — which it does. From the person I was replying to: > We might find that every N years a new disease emerges, spreads, and then is adapted to - and we're just lucky enough to be around to observe this current wave Sickle cell seems like precisely that in response to malaria, in human history. In addition to sickle cell as a trait which shows that adaptation, our DNA is full of evidence of wide spread viruses, eg wide spread infection, because of the patterns in junk DNA. It’s not just mutation — it’s also a chemical signature of the rate of retrovirus epidemics. Your post seems not to have understood mine, talking about nonsense with radiation — which is nonsense because I never mentioned a means of adaptation, but merely signatures of historic disease spread (and a case of adaptation).
- TheSpiceIsLife 8y ago
  Further to this, isn't this the basis for evolution? Some selective pressure emerges that didn't previously exist, whether that be a predator; change in nutrient availability; disease; climate; etc. It's possible the loss of habitat in Tasmania has either slowed spread of the DFTD, because the Devils are more widely dispersed, or hastened the spread because there are fewer Devils reproducing to potentially adapt to it. I find it interesting to ponder how it has come about that the Earth isn't just covered in, say, that pathogenic fungus¹ reported on recently, but rather something like 8.7 million species². 1. https://news.ycombinator.com/item?id=19515362 https://news.ycombinator.com/item?id=19515362 2. https://www.nature.com/news/2011/110823/full/news.2011.498.html https://www.nature.com/news/2011/110823/full/news.2011.498.h...
  - dmix 8y ago
    The answer to your question is probably the same: natural selection and the general competition between species (and pathogens).
  - akiselev 8y ago
    > I find it interesting to ponder how it has come about that the Earth isn't just covered in, say, that pathogenic fungus¹ reported on recently, but rather something like 8.7 million species². Existing inside an organism with a functioning immune system long enough to cause death requires completely different adaptations than existing outside of one. By their very nature, most pathogens spend too much energy on biochemistry that does diddly squat (without an immune system to fight) to help them compete against the innumerable species of garden variety bacteria floating around.
im3w1l 8y ago
What happened was that a cell from one tasmanian devil mutated into a unicellular parasite. This parasite is now spreading from animal to animal. The reason they didn't have problems before was that the parasite didn't exist before.
anonlastname 8y ago
This is because at one point the Tasmanian devil population completely crashed and much of the genetic variation in their population was lost. This is literally a textbook example of something called the "founder effect." The result is that the Tasmanian devils alive today are genetically close enough for their immune systems not to reject each other's cancer.
askvictor 8y ago
Another factor is that there is a psychical barrier (mountain range) that effectively keeps two populations separate; one of those populations is affected, the other is not. One of the 'plan b's was that even if one population went extinct, it could be repopulated from the other.
bamboozled 8y ago
I believe they’re not extinct because the specifies mostly survived by living in captivity and being cared for by teams of scientists. If I remember correctly it was only recently they were reintoduced into the wild en-masse.

notavalleyman 8y ago

Just speculating here, but there might not be anything temporally "special" about the spread of infection right now. We might find that every N years a new disease emerges, spreads, and then is adapted to - and we're just lucky enough to be around to observe this current wave

FakeComments 8y ago
Surely this must be true given all the weird junk in our DNA and specialized traits like the genes that cause sickle cell, but resist malaria. https://www.cdc.gov/malaria/about/biology/index.html https://www.cdc.gov/malaria/about/biology/index.html
- Nasrudith 8y ago
  That is true but sickle cell isn't the best example for that. It is essentially a 'useful glitch' of a trait as opposed to something viral. There are ancient viruses embedded in human DNA. Effectively the embedding is just another form of mutation to the genome (although there are distinct patterns). It gets embedded regardless if it is copying errors, mutagenic chemicals, or electromagnetic radiation in cause. https://www.nytimes.com/2017/10/04/science/ancient-viruses-dna-genome.html https://www.nytimes.com/2017/10/04/science/ancient-viruses-d... Theoretically it /is/ possible for the right sequence of say radiation damage and auto-repair to give rise to segments of a virus in DNA but the odds are stupidly lower. To use an example technically you could scatter scrabble tiles randomly to get quotes from Shakespeare if you do it enough but you are far more likely to occasionally get gibberish than "WHAT LIGHT THROUGH YONDER WINDOW BREAKS" - let alone in the right order.
  - FakeComments 8y ago
    I’m not sure I follow what you’re saying. Nobody claimed sickle cell had anything to do with viruses; I claimed that sickle cell is a mutation which provides a protection to malaria — which it does. From the person I was replying to: > We might find that every N years a new disease emerges, spreads, and then is adapted to - and we're just lucky enough to be around to observe this current wave Sickle cell seems like precisely that in response to malaria, in human history. In addition to sickle cell as a trait which shows that adaptation, our DNA is full of evidence of wide spread viruses, eg wide spread infection, because of the patterns in junk DNA. It’s not just mutation — it’s also a chemical signature of the rate of retrovirus epidemics. Your post seems not to have understood mine, talking about nonsense with radiation — which is nonsense because I never mentioned a means of adaptation, but merely signatures of historic disease spread (and a case of adaptation).
TheSpiceIsLife 8y ago
Further to this, isn't this the basis for evolution? Some selective pressure emerges that didn't previously exist, whether that be a predator; change in nutrient availability; disease; climate; etc. It's possible the loss of habitat in Tasmania has either slowed spread of the DFTD, because the Devils are more widely dispersed, or hastened the spread because there are fewer Devils reproducing to potentially adapt to it. I find it interesting to ponder how it has come about that the Earth isn't just covered in, say, that pathogenic fungus¹ reported on recently, but rather something like 8.7 million species². 1. https://news.ycombinator.com/item?id=19515362 https://news.ycombinator.com/item?id=19515362 2. https://www.nature.com/news/2011/110823/full/news.2011.498.html https://www.nature.com/news/2011/110823/full/news.2011.498.h...
- dmix 8y ago
  The answer to your question is probably the same: natural selection and the general competition between species (and pathogens).
- akiselev 8y ago
  > I find it interesting to ponder how it has come about that the Earth isn't just covered in, say, that pathogenic fungus¹ reported on recently, but rather something like 8.7 million species². Existing inside an organism with a functioning immune system long enough to cause death requires completely different adaptations than existing outside of one. By their very nature, most pathogens spend too much energy on biochemistry that does diddly squat (without an immune system to fight) to help them compete against the innumerable species of garden variety bacteria floating around.

im3w1l 8y ago

What happened was that a cell from one tasmanian devil mutated into a unicellular parasite. This parasite is now spreading from animal to animal. The reason they didn't have problems before was that the parasite didn't exist before.

anonlastname 8y ago

This is because at one point the Tasmanian devil population completely crashed and much of the genetic variation in their population was lost. This is literally a textbook example of something called the "founder effect." The result is that the Tasmanian devils alive today are genetically close enough for their immune systems not to reject each other's cancer.

askvictor 8y ago

Another factor is that there is a psychical barrier (mountain range) that effectively keeps two populations separate; one of those populations is affected, the other is not. One of the 'plan b's was that even if one population went extinct, it could be repopulated from the other.

bamboozled 8y ago

I believe they’re not extinct because the specifies mostly survived by living in captivity and being cared for by teams of scientists. If I remember correctly it was only recently they were reintoduced into the wild en-masse.