Saturday, 3 September 2016

Tasmanian devils got rid of their cancer

Since 1996, the population of tasmanian devils have been decimated by a contagious cancer. Recently, it has been discovered that the tasmanian devils have developed a resistance to this cancer.


Devil Facial Tumour Disease

The contagious cancer affects tasmanian devils and gives them facial tumours. These tumours begin as lumps around the mouth area and can spread to the rest of the body. They can affect the devils by preventing them from eating, giving them infections or causing their organs to fail. All of these usually lead to the death of the animal within about 6 months.
Tasmanian Devil with tumors


Lots of biting
The disease spreads when the devils bite each other. Since the disease is spread this way, it is easily propagated through a colony since they bite each other very frequently. A lot of Tasmanian devils’ social interactions are based on biting, for example when they fight.  As well as this, the tasmanian devils are thought to have a very low genetic diversity which lowers their chances of resistance to disease. This means that the devils aren’t very different from each other, so if the cancer can harm one Tasmanian devil, it can harm the other devils too. This gave the disease a very easy way to make it around nearly all the colonies.

Image result for tasmanian devil biting
Fighting Tasmanian Devils

Immune
But now, because of an accidental change in the Tasmanian Devils’ DNA, their genetic code, they’re now immune to the contagious cancer. They can’t get the disease anymore. And the best thing is, when they begin to reproduce, the next generation of tasmanian devils will have the immunity as well. Over time, maybe all Tasmanian Devils will have be immune and the cancer will go extinct.

That’s odd...
Scientists discovered this by comparing the genome of the immune tasmanian devils with that of a past tasmanian devil which existed before the tumor had begun. They realized that there was a difference in the actual genetic makeup of the tasmanian devils. This genetic change happened in seven different genes. Five of those are related to immune response against cancer in other mammals such as ourselves. But, the most amazing part of this discovery is that this immune response has happened very quickly. This entire immunity was evolved over just about five generations, which is around twenty years. This evolution can be compared to rabbits when a disease called myxomatosis began to affect Australia. The only difference is that the rabbits took much longer to become immune.


Looking into the future
This exciting new discovery could affect the future of cancer treatment. With the new technological advances which are being made in the realm of genetics, we might soon be able to use this discovery as a cure for cancer. This could be possible since these genetics are similar in other mammals.

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Sources:
http://www.pnas.org/content/108/30/12348
http://www.nature.com/ncomms/2016/160830/ncomms12684/full/ncomms12684.html
https://www.sciencemag.org/news/2016/08/tasmanian-devils-are-rapidly-evolving-resistance-contagious-cancer
https://en.wikipedia.org/wiki/Devil_facial_tumour_disease
http://www.upi.com/Health_News/2015/12/30/Second-form-of-contagious-cancer-found-in-Tasmanian-devils/4961451508112/
Di Giallonardo, F. & Holmes, E. C. Viral biocontrol: grand experiments in disease emergence and evolution. Trends Microbiol. 23, 83–90 (2015)
Epstein, B. et al. Rapid evolutionary response to a transmissible cancer in Tasmanian devils. Nat. Commun. 7:12684 doi: 10.1038/ncomms12684 (2016)
http://animals.nationalgeographic.com/animals/mammals/tasmanian-devil/