In ancient Greek mythology, one of the most famous monsters is the Hydra - a mythical, reptilian creature with the ability to regrow any of its multiple, snakelike heads. As it turns out, this seemingly magical power is based (at least partly) in scientific truth. Autotomy is the scientific term that describes a lizard’s ability to regrow its tail. Although humans have been aware of this phenomenon for countless years, scientific research has yet to figure out how these creatures pull it off…until now.
Wonders of the 326 genes
After analyzing the genetic makeup of various lizards, researchers were able to isolate a group of 326 genes that “lit up” when tail regeneration took place. These genes were all active inside the lizard’s tail, and scientists were surprised by the complexity of the process. They theorized that regeneration would take place only on the tip of the tail, but discovered instead that genes were being “turned on” throughout the muscles, cartilage, and the spinal column of the entire limb.
Lizards typically lose their tails as a defense mechanism. When chased by predators, they detach their tails to confuse predators and give them a few vital seconds to make their getaway. Geckos, salamanders, and anoles can all lose their tails and regrow them. Typically, it takes lizards about two months before they have a new, fully functioning tail. Geckos are the fastest regenerators, and they can regrow their tails in just 30 days.
Lizards aren’t alone
Lizards aren’t the only creatures born with interesting regenerative abilities. Take the Axolotl, for instance - an amphibian with astounding regenerative abilities. Some Axolotls can even re-generate certain parts of their brain. Salamanders can regenerate their hearts and entire limbs. The jellyfish Turritopsis dohrnii is effectively immortal, with the ability to theoretically live forever by reverting back to its polyp stage again and again.
Lizards may help us revolutionize health as a whole
So why does all of this matter? Isn’t it obvious? By studying these animals, we might be able to “learn some of their tricks” and use them to improve medical science on an astronomical level. Theoretically, we may be able to study the genetic makeup of these animals and develop treatments that could mimic some of their regenerative abilities. This is exactly what researchers had in mind when they were attempting to isolate the genes responsible for tail regeneration in lizards. Now that they’ve accomplished this monumental achievement, they can move on to the next step. Here’s the most encouraging discovery so far: most of the genes responsible for tail regeneration in lizards are also present in human DNA. To put it simply, all we need to do now is find a way to “encourage” these genes to act in the same way they do in lizards’ tails. Easier said than done. What these researchers are alluding to is essentially gene therapy - an experimental approach to treating illnesses and diseases. Although gene therapy has overcome major hurdles over the last few years, reliable treatment in this form is probably a long way off. There are many risks involved with this process, and we still don’t fully understand the human genome (although we like to think we do). Because of this, inserting or activating certain genes could have unforeseen, negative effects on our bodies. The most promising applications for this line of research has to do with spinal cord injuries. The interesting thing about lizard tails is that they contain the animal’s spinal cord. In contrast, a mammal’s tail does not contain a spinal column. This means that when a lizard regrows their tail, they’re actually regrowing their spinal column. If we could develop a treatment that activates the lizard’s genetic “recipe” that fuels regeneration, we may be able to “encourage” the human spinal column to repair itself.
Because gene therapy is still somewhat controversial, it’s unlikely that we’ll see real treatments as a result of this research anytime soon. Researchers are also suggesting this genetic breakthrough could lead to a treatment for arthritis. Is curing your stiff joints worth taking a risk with gene therapy? Probably not. On the other hand, what if you had suffered a serious spinal injury? Wouldn’t you do anything to recover? In this case, taking a leap of faith with an experimental new treatment based on lizard genes might seem like an attractive prospect.