Lizards May be the Key to Regenerating Limbs

Lizards may be the key to unlocking the mystery of limb regeneration, according to new research. Scientists have discovered the genetic "recipe" for lizard tail regeneration, which may lie in a goldilocks mixture of certain genes.

The research team used next-generation molecular and computer analysis tools to examine the genes turned on in tail regeneration - specifically, they looked at the green anole lizard (Anolis carolinensis).

The findings were published in the journal PLOS ONE.

"Lizards basically share the same toolbox of genes as humans," lead author Kenro Kusumi, a professor in Arizona State University's School of Life Science, said in a statement.

"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," he explained.

In their analysis, researchers discovered what is called the "Wnt pathway" - a process that is required to control stem cells in many organs such as the brain, hair follicles and blood vessels. Other animals like salamanders, frogs, tadpoles and fish can also regenerate their tails, but lizards have a unique pattern of tissue growth that is distributed throughout the tail, not just at the tip like other animals.

Though, researchers note that tail regeneration is not something that happens overnight. It usually takes these reptiles more than 60 days to completely develop a new, functional tail.

After investigating this complex process, the ASU team identified one type of cell that is important for tissue regeneration.

"Just like in mice and humans, lizards have satellite cells that can grow and develop into skeletal muscle and other tissues," said co-author Jeanne Wilson-Rawls.

Researchers are hopeful that if this unique gene sequence is applied to humans, one day it could lead to the regeneration of new cartilage, muscle or even spinal cord.