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ANDREW STROFER: Now Tasmanian devils are marsupials, so
they're a type of mammal that has a pouch to hold their young
just like kangaroos. And they're from Australia. They
originally were found on the mainland Australia and the
island of Tasmania. And a few hundred years ago, they went
extinct on the mainland and now are only found in Tasmania,
which is a small island south of Melbourne and off of the
southern coast of Tasmania. Another interesting fact about
Tasmanian devils is that they're carnivorous marsupials. That
is, they're meat-eaters. Most of these marsupials, like
kangaroos, only are vegetarians. That is, they're herbivores.
So Tasmanian devils are now the world's largest carnivorous
marsupial after the Tasmanian tiger went extinct, probably
sometime in the 1940's.
We're not sure exactly how the devils originally got Tasmanian
devil facial tumor disease. It started in the northeastern part
of Tasmania and was first discovered in 1996. And since
then, it's caused by an infectious cancer.
That is, although we're finding out that a lot of cancer is
maybe associated with viral infections, this is
actually a tumor and cancer that's transmissible
from one individual to another. And so this cell line has now
moved through thousands of devils and about 80% of the way
across Tasmania, leaving populations highly decimated as
it's gone through.
From the first standpoint, this rare, infectious cancer is a
fascinating disease to begin with. How is it that
individuals are susceptible to a cancer that's found in another
individual? And this is – there's only a couple of other
instances of infectious cancers that we know about in the animal
kingdom, which includes a cancer that is transmitted as a
venereal disease between dogs and one that was found in
Siberian hamsters in a laboratory setting several years
ago. So one of the big questions is – of course, we're
concerned a lot about cancers in humans – is: Why is this
particular type of cancer infectious from one individual
to another? And why is it so long-lived because we know that
cancer cells generally are very unstable. So from a general
health stamping, this cancer can be used as a model to maybe
increase our understanding of how cancers operate in general.
But one of the big questions for Tasmanian devil is: Some of the
current models predict that the cancer will actually cause
extinction in devils. And so this is an iconic animal from
Australia. Of course, in the US we made a cartoon character
about it. And so we're really concerned about this –
preserving this animal as part of the natural history of
Australia. But another really interesting question is:
We want to actually – so the goal of this research is to
actually predict disease transmission in populations
that are uninfected.
We'll be using genomic analyses of devils that actually have
survived the infections in old populations that have been
infected for a while to see what parts of their genome give them
resistance, seem to be giving them resistance, to the tumor.
And then we can look for devils that may have those similar
genomic components in new populations that are uninfected.
So another conservation goal of this work is to actually take
those devils that seem to have the genetic components that make
them the most highly resistant and use those to help populate
captive breeding programs off the main island of Tasmania, in
order to protect devils if they do, unfortunately, go extinct on
the mainland of Tasmania.