Informant38

chop off a salamander's leg:

Chop off a salamander's leg and a brand new one will sprout in no time. But most animals have lost the ability to replace missing limbs. Now, a research team at the Salk Institute for Biological Studies has been able to regenerate a wing in a chick embryo - a species not known to be able to regrow limbs - suggesting that the potential for such regeneration exists innately in all vertebrates, including humans.
Their study, published in the advance online edition of Genes and Development on Nov. 17, demonstrates that vertebrate regeneration is under the control of the powerful Wnt signaling system: Activating it overcomes the mysterious barrier to regeneration in animals like chicks that can't normally replace missing limbs while inactivating it in animals known to be able to regenerate their limbs (frogs, zebrafish, and salamanders) shuts down their ability to replace missing legs and tails.

EurekAlert! 17.Nov.06
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But how will we perfect the technique in humans?
I know! We'll use that bucket of stem cells we've got out back in the shed!
But seriously, folks.
These steps lead right to the threshold of immortality - physical immortality.
And the pigs at the top of the food chain are going to be first in line.
For immortality.
Cool.
Chop off a salamander's leg...