With the help of scientists, the lizard has restored its perfect tail for the first time in more than 250 million years.

Lizards can grow new tails, but they will no longer be as good as the old one. The first tail contains all the vertebrae and nerves, and the subsequent ones contain only the cartilaginous tube.

The authors of the new work from the University of Southern California used stem cell therapy to restore the lizards to the same perfect tail as the original.

To do this, scientists studied how the tails of lizards grow during embryonic development and in adulthood, after they fall off. It turned out that in both cases, neural stem cells (NSC) play the main role, but they behave differently.

Adult NSCs produce a molecular signal that blocks skeletal and nerve formation and stimulates cartilage growth. Therefore, instead of an ideal tail, a cartilaginous tube is formed. In embryos, a full-fledged tail is formed, but the transfer of embryonic cells to adults who have lost their tail did not work.

The researchers decided to use genetic editing tools and made embryonic cells immune to molecular signals. As a result, they were able to restore perfect tails with skeletal and nerve tissue.

The authors are going to improve the new method to use it for hard-to-heal wounds.