Study shows humans may one day re-grow limbs

The fact that lizards can re-grow limbs is pretty special. They can escape predators by not fighting for a tail, only to have a fully refurbished model in a few months' time. That little trick may be coming to humans, too, if scientists have their way.

A team of researchers from Arizona State University have discovered the genetic "recipe" for limb regeneration in lizards. Though the details are likely complicated for you or I, the team is examining genes that are activated in the process of tail regeneration. In doing so, they hope to hack their way into genetic alterations in humans — someday.

Kenro Kusumi, a professor at Arizona State University's School of Life Sciences, is the lead on this study. According to him, humans aren't far off from limb regeneration, so long as we find the right balance:

Lizards basically share the same toolbox of genes as humans. Lizards are the most closely-related animals to humans that can regenerate entire appendages. We discovered that they turn on at least 326 genes in specific regions of the regenerating tail, including genes involved in embryonic development, response to hormonal signals and wound healing.

Using next-generation technologies to sequence all the genes expressed during regeneration, we have unlocked the mystery of what genes are needed to regrow the lizard tail. By following the genetic recipe for regeneration that is found in lizards, and then harnessing those same genes in human cells, it may be possible to regrow new cartilage, muscle or even spinal cord in the future.

Study co-author Jeanne Wilson-Rawls says the team is already discovering what makes regeneration tick. "We have identified one type of cell that is important for tissue regeneration," she said. "Just like in mice and humans, lizards have satellite cells that can grow and develop into skeletal muscle and other tissues."

For those who have long marveled at the ability to regrow appendages, and quietly wished they could do the same, this is pretty neat. Though we don't have to lose an arm to escape a Mongoose, this could eventually be handy for medical cases where a limb is lost to disease or injury. As cool as engineered spring-loaded legs are, there's still no substitute for flesh and bone.