How salamanders can regrow nearly complete tails but lizards can’t | Science News

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Mystery Solved

How salamanders can regrow nearly complete tails but lizards can’t

Neural stem cells in the spinal cord prevent the reptiles from regenerating nerve cells

By
12:30pm, August 17, 2018
an axolotl and a green anole

TAIL TROUBLE  Salamanders such as the axolotl (above) can regrow nearly perfect tails, including missing nerve cells. Lizards such as the green anole (below) can’t. 

Salamanders and lizards can both regrow their tails, but not to equal perfection.

While a regenerated salamander tail closely mimics the original, bone and all, a lizard’s replacement is filled with cartilage and lacks nerve cells. That contrast is due to differences between stem cells in the animals’ spinal cords, researchers report online August 13 in Proceedings of the National Academy of Sciences.

When a salamander loses its tail, neural stem cells in the creature’s spinal cord can develop into any type of nervous system cell, including nerve cells, or neurons. But through evolution, lizard neural stem cells “have lost this ability,” says study coauthor Thomas Lozito, a biologist at the University of Pittsburgh. Lizards, while they can regrow cartilage and skin, cannot regenerate neurons, the researchers found.

Lozito and colleagues

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