Have you ever heard the myth that kids under the age of eleven can re-grow a severed fingertip?
Gruesome thought, but the answer is, yes, kids under eleven have been known to regenerate fingertips.
This phenomenon could give scientists a clue as to how they might one day engineer humans to re-grow not only fingertips but entire limbs, just like starfish and salamanders.
Just as salamanders re-grow their tails, humans may someday be able to regenerate lost limbs! Scientists don't understand exactly how this works in starfish and salamanders, either, but there's a possibility that it has something to do with a pathway of molecular chemical signals in these animals.
When a starfish loses an arm, these signals may direct cells in the vicinity of the lost limb to act like embryonic stem cells. Scientists assume the stem cell-like cells, which can become any kind of cell, turn themselves into arm cells and re-grow the missing arm.
What scientists do know is that the same pathway of molecular signals exists in all mammals, including humans. Studies with chicken embryos have shown that enhancing the pathway can help them regenerate lost wings. This makes scientists very curious about what could happen if the same pathway were enhanced in humans.