Scientists Find Genetic Root of Limb Regrowth

If you’ve ever been jealous of a lizard’s ability to regrow its tail, take heart: Scientists are one step closer to understanding how it works and say that one day we might be able to do the same thing. (With arms and legs, that is. Not tails. Be realistic.) They published their findings in the journal PLOS One.

Few things are cooler (and more useful) than the ability to regenerate lost limbs. So it’s not too surprising that scientists are really, really interested in how it all works. Researchers at the MDI Biological Laboratory in Maine were especially curious about the inner workings of a process called blastema formation, in which new limb tissue begins to grow at the site of a wound. They decided to look at three species with appendage-regenerating superpowers: the zebrafish (Danio rerio), the bichir fish (Polypterus senegalus) and Ambystoma mexicanum, better known as the Mexican salamander or axolotl. Despite this common trait, these species are evolutionarily distant from one another, having diverged about 420 million years ago.

In order to study limb regrowth, the scientists had to start with limb loss. They brought groups of axolotls, bichirs, and zebrafish into the lab and surgically amputated at least one appendage on each animal—legs for the axolotls and fins for the fish. Then they let the animals rest, collecting tissue samples from the wound sites every few days. They ran the tissue samples through a series of genetic tests, examining several types of each animal’s RNA in search of regrowth-related code.

Not only did they find that code, but they found the same code in all three species—a surprising and exciting twist. "It was a fantastic feeling," co-author Benjamin L. King said in a press statement. "We didn't expect the patterns of genetic expression to be vastly different in the three species, but it was amazing to see that they were consistently the same."

Understanding blastema formation could help explain the complicated science of wound and other tissue healing, and may someday lead to treatments for people who have suffered injuries or burns.

Co-author Voot P. Yin also notes that the regrowth mechanism they found may exist in many other species as well—including humans.

"Limb regeneration in humans may sound like science fiction, but it's within the realm of possibility," Yin said. "The fact that we've identified a genetic signature for limb regeneration in three different species with three different types of appendages suggests that nature has created a common genetic instruction manual governing regeneration that may be shared by all forms of animal life, including humans."

So don’t give up on your lizard dreams just yet.

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