Maria Konovalenko looks at research into salamander biochemistry: "By tracking individual cells in genetically modified salamanders, researchers have found an unexpected explanation for their seemingly magical ability to regrow lost limbs. Rather than having their cellular clocks fully reset and reverting to an embryonic state, cells in the salamanders' stumps became slightly less mature versions of the cells they'd been before. The findings could inspire research into human tissue regeneration. ... The cells don't have to step as far back as we thought they had to, in order to regenerate a complicated thing like a limb. There's a higher chance that human or mammalian cells can be induced into doing the same thing. ... People working on stem cells are trying to de-differentiate cells in an artificial fashion. It will be very important for the regenerative-medicine community to take stock of what's going on in the salamander, because they've been doing it for 360 million years, and found a natural way to de-differentiate their tissues."

Link: http://mariakonovalenko.wordpress.com/2010/11/01/discovery-in-salamanders-could-lead-to-human-limb-regeneration/