海角大神

Regrown limbs sounds like a creepy scenario from a science fiction movie, but for salamanders it is reality.聽

And they're not alone. Now researchers found that limb regeneration has origins deep in the history of life on Earth.

Fossilized four-limbed animals from some 290 million years ago also , according to a study聽published Monday in the journal聽Nature.

These ancient specimens suggest that regeneration was more widespread among ancient four-limbed vertebrates, known as tetrapods, at the time than it is in modern ones.聽

鈥淏y looking at some of these extinct organisms, we鈥檝e been able to figure out that this ability to regenerate is actually very old and is much more common among animals than we thought,鈥� study co-author Jennifer Olori, a vertebrate paleontologist at SUNY Oswego, tells 海角大神 in an interview.

鈥淯ntil our work, it was really only known to be, the amazing powers of limb regeneration, in salamanders and a little bit of regenerative properties in lizards and also a little bit in frogs and in lungfishes, but not to the degree that we see in salamanders,鈥� says Dr. Olori.聽

Lizards, for example, can regenerate their tails, but the new tails lack the same skeletal properties as the original tail. Instead, she explains, they just produce some featureless cartilage.聽But salamanders can regrow a new limb with all the same bones, muscles, and nerves.

Sometimes those new salamander legs don鈥檛 grow back perfectly, or a 鈥渇inger鈥� isn鈥檛 quite the same.聽

The researchers found similar digit abnormalities in fossils of ancestors of modern salamanders, suggesting that they, too, had this peculiar regeneration ability.

鈥淲e saw some similar patterns that we see in living things when they regenerate, like having parts of the limb that lag behind or move ahead of other parts of the limb in terms of their development,鈥� says Olori.

鈥淭he upper part of the arm might be very well developed, for example, and the lower part of the arm be less developed, showing that there鈥檚 sort of a difference in timing there and that part of it may have regenerated,鈥� she says.

Or perhaps a tail might be caught in regeneration, with some vertebrae well formed, while others were still in the formation stages, Olori says.

What's more, it wasn鈥檛 only salamander鈥檚 ancestors that had this ability.聽Some of these extinct tetrapods were actually more closely related to reptiles and mammals than to amphibians.

Knowing that, Olori says, 鈥淲e can infer that this is an inherited trait that they actually got from their common ancestor a very long time ago, hundreds of millions of years ago.鈥�

So the fossils these researchers examined may not have been among the first animals to undergo limb regeneration. The ability may be much older than 290 million years.聽

鈥淲e鈥檝e put forth a new hypothesis about where regeneration might have originated, suggesting that it鈥檚 really old and very common,鈥� says Olori.