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
2. https://www.nature.com/news/2011/110823/full/news.2011.498.h...
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.
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.
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).
The reason they didn't have problems before was that the parasite didn't exist before.
If I remember correctly it was only recently they were reintoduced into the wild en-masse.