anthropometaphors

translating biophilia into a love of life

Genetic retaliation

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Tasmanian devil (Sarcophilus harrisii)

The first entry made on anthropometaphors was prompted by learning about the evolution of a contagious facial cancer that has rapidly spread through wild Tasmanian devils, killing most adults in affected populations.  On the right is a picture of the poor guys, before (cute!) and after (sad!).

I’ve followed the evolution (so to speak) of this issue, and spied an article in the 14 July 2008 issue of PNAS demonstrating life-history changes in devil populations affected by the facial tumor disease.  In particular, at four of the five devil sites studied, researchers found evidence for breeding several months to a year earlier than the normal breeding age of 2-years-old. In evolutionary speak, what could be happening is co-evolution.  Also known as The Red Queen Hypothesis, organisms can drive each other toward adaptation and evolution in a race to survive.  In the words of Lewis Carroll’s Red Queen,

“It takes all the running you can do, to keep in the same place.”

Consider this: at an unknown time in the past, a strain of cancer somehow gained an adaptation enabling it to spread between individual devils.  What could be happening now is a genetic retaliation on the part of the devils; an evolutionary adaptation to breed earlier, before the onset of cancer, allowing the survival of the species. While further studies are required to confirm devils are reproducting earlier as a result of adaptation (rather than say, increased availability to food or mates), the plight of these devils is in the evolutionary spotlight.  Tasmanian devils may be the first known mammal to rapidly evolve it’s reproduction patterns in response to disease.

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Written by morethangray

July 15, 2008 at 2:02 pm

Posted in thoughts

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