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Zebrafish Regenerative Ability May Lead To Help In Humans
esocid tips us to news out of Duke University Medical Center, where researchers have discovered a type of microRNA that is related to the ability of zebrafish to regenerate lost or damaged organs. This is the result of a study initiated after it was discovered that zebrafish were able to recover from "massive injury" to the heart through their own regenerative biology. The scientists hope to be able to use this information to bring about similar healing in humans. Zebrafish have also been helpful in cancer research.
"In zebrafish, one or more microRNAs appear to be important to keep regeneration on hold until the fish needs new tissue, the Duke researchers say. In response to an injury, the fish then damp down levels of these microRNAs to aid regrowth. Poss and many other cell biologists believe that mammals may have the same tissue regeneration capability as zebrafish, salamanders and newts, but that it is locked away somewhere in our genome, silenced in the course of evolution."
if i had a tail i'll play with it all day...
AGH! I have ears regenerating all over my body! Get them off!
Once you start despising the jerks, you become one.
That would be my guess. There's a good bit of research where they tinkered with mouse genes to accelerate or slow telomere erosion, and found that the natural mouse is pretty close to the maximum lifespan possible. Faster erosion causes the mice die of old age sooner, but slower erosion results in more cancer deaths.
Regeneration may well have similar costs. Since all of the natural regenerators are poikilotherms, I would speculate that their overall lower metabolic rate has less risk of cancer. Giving up regeneration may well be the price we pay for warm blood.
Lacking <sarcasm> tags,
... what is the evolutionary benefit that mammals get from not regenerating?
Given the hostile everyday nature of the wild, an animal has a far better chance of surviving in the long run if he gets back on his feet after an injury even if it isn't a full one. Its far quicker for scar tissue to reform than it is to recreate all the tissue back in a perfect fashion.
So rather having an open wound for several weeks on on end, a wild mammal would have a scab within 24 hours and then later initial scar tissue within a week
"I am the king of the Romans, and am superior to rules of grammar!"
-Sigismund, Holy Roman Emperor (1368-1437)
I recently contacted Ellen Heber-Katz, asking how the regenerating mice were progressing; they have not published anything about them in nearly two years. She replied that the mice are in fact still alive and breeding, which means that they have passed their life expectancy by at least half a year. She also said they will be releasing "lots of papers" in 2008.