October 10, 2012
Regenerated Lizard Tails Not A Perfect Match To Original Tail
Lawrence LeBlond for redOrbit.com - Your Universe Online
Some lizards have the innate ability to re-grow their tails when their original one gets severed. However, this natural regenerative ability does not occur in a perfect way. In other words, the new tail, based on studies by a team of scientists from two Arizona schools, is quite different from the original appendage it replaces.
Scientists from Arizona State University and University of Arizona examined the anatomical and microscopic make-up of regenerated lizard tails and published their findings in a pair of articles featured in the October issue of the journal, The Anatomical Record.
Rebecca Fisher, an associate professor in ASU's School of Life Sciences, and at the UA College of Medicine in Phoenix, said: “The regenerated lizard tail is not a perfect replica“¦There are key anatomical differences including the presence of a cartilaginous rod and elongated muscle fibers spanning the length of the regenerated tail.”
In their studies of one particular type of lizard--the Green Anole (Anolis carolinensis)--the researchers found that when this reptile loses its tail due to an injury or other incident, it can grow a new one in place of the old. However, the new tail had a single, long tube of cartilage rather than a vertebrae, as seen in the original tail. Also, long muscles span the length of the new tail compared to shorter muscle fibers found in the original.
The findings suggest the new tail is “less flexible” and not “capable of the fine movements of the original tail, with its interlocking vertebrae and short muscle fibers,” said Fisher. “The regrown tail is not simply a copy of the original, but instead is a replacement that restores some function.”
While this regenerated tail is quite different than the original, the whole idea of being able to regenerate a hyaline cartilage skeleton and make new muscle is very interesting to researchers who believe the regeneration skills found in these reptiles could one day have beneficial implications for humans.
“Using next-generation technologies, we are close to unlocking the mystery of what genes are needed to regrow the lizard tail,” said study coauthor Kenro Kusumi, an associate professor in ASU's School of Life Sciences in the College of Liberal Arts and Sciences. “By supercharging these genes in human cells, it may be possible to regrow new muscle or spinal cord in the future.”
Jeanne Wilson-Rawls, associate professor in the School of Life Sciences, added that “these studies lay the groundwork for understanding how new cartilage and muscle are elaborated by lizards“¦The next step is understanding the molecular and cellular basis of this regeneration.”
The research team also found the presence of pores in the regenerated cartilage tube of the tail. While the original tail is made up of many bones, with blood vessels and nerves passing throughout the tail, in the regenerated tube, blood vessels only pass through the tube pores. This suggests that nerves from the original tail stump grow into the regenerated tube.
This finding could also offer hope in finding new therapeutic approaches to spinal cord injuries and diseases in humans.