

Scientists Demonstrate Mammalian Regeneration Through a Single Gene Deletion - dpurp
http://www.sciencedaily.com/releases/2010/03/100315161913.htm

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Zak
I think an important question to research here is why p21 evolved in mammals.
The article says knocking it out doesn't appear to increase cancer rates,
which would have been my first and only guess.

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lotusleaf1987
Maybe somehow it speeds up the system of evolution by keeping life
expectancies shorter, thereby increasing turnover (death and new births)? I
have no clue just throwing that out there.

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srean
To survive natural selection the gene must give the animal some reproductive
advantage. I can understand that promoting longevity beyond the reproductive
stage of one's life cycle affords no such benefit. But one still has to
account for the fact that the lack of the gene appears to increase the
survivability in the reproductive pahse as well. Something more must be going
on.

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ckuehne
Strictly speaking, it must give the _gene_ a reproductive advantage, not
necessarily the animal. Often, these two advantages are aligned. But they need
not be. This is the case in kin altruism. And this is also, why "promoting
longevity beyond the reproductive stage of one's life cycle" affords sometimes
very much such benefits. Example: grandparents can help raising their
children's children (and their children's children's children ;)). Kin
altruism becomes even more apparent in ants (or other social animals). Worker
ants or bees are pretty much infertile but they help a lot.

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btilly
It should be noted that the difference is much more extreme for ants than it
can be for mammals due to a genetic quirk where a female ant shares 50% of her
genes with her children and 75% with her sisters. (Therefore having more
sisters is better than having children.)

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ckuehne
Still there are mammals that live eusocial. The naked mole rat comes to mind.

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modeless
They don't mention regenerating anything specific besides holes in ears. Can
these mice regenerate digits? Whole limbs? Internal organs? Spinal column
damage?

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pygy_
Google? If you follow the link at the bottom of the article will lead you to
the PNAS paper. You'll learn that the mice strain is called MRL[1].

It can regenerate its ears, cartillage[2], cardiac muscle after cold-induced
lesions[3] but sadly not after infarction/reperfusion[4] and digits (to some
extent, in neonate mice)[5]. There may be more.

[1] <http://www.pnas.org/content/107/13/5845.full>

[2][http://www.eurekalert.org/pub_releases/2001-08/wi-
rit080201....](http://www.eurekalert.org/pub_releases/2001-08/wi-
rit080201.php)

[3] <http://www.pnas.org/content/98/17/9830.full>

[4]
[http://onlinelibrary.wiley.com/doi/10.1111/j.1067-1927.2005....](http://onlinelibrary.wiley.com/doi/10.1111/j.1067-1927.2005.130212.x/full)

[5]
[http://onlinelibrary.wiley.com/doi/10.1111/j.1524-475X.2007....](http://onlinelibrary.wiley.com/doi/10.1111/j.1524-475X.2007.00216.x/abstract)

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6ren
I expect the full effects are not very dramatic, else it would have been
noticed earlier, since MRL are commonly used in experiments.

I find it reassuring that this unknown thing was right on our doorstep, and it
makes me wonder what other amazing discoveries are just out of reach (or even
within reach...) The world is more complex than we see; all we need do is look
(a lot...) \- _There is more in heaven and earth than is dreamt of in your
philosophy, Horatio_ \- _Nature's imagination is greater than your
imagination_

From the article, it seem to not be so much that it enables healing, but that
it enables healing without scars. I expect this is crucial in some situations,
but it's not clear that it can heal what wouldn't otherwise heal. Certainly,
there are cosmetic applications.

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pygy_
It was noticed in the nineties. The genetic substrate was discovered this
year.

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schwit
This story is from Mar. 16, 2010

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tocomment
I wonder what's happened since then? You'd think we'd really jump on this kind
of science. I wonder why all this stuff is so slow.

~~~
eru
Science takes as long as writing computer programs.

