by Abigail Mullen
Salamanders have proven to be excellent models in developmental, regeneration and evolutionary studies. According to Nature, the Mexican axolotl, Ambystoma mexicanum, has been grown in labs and studied due to their remarkable ability to regenerate limbs with bones, muscles and nerves within weeks. Even more interesting, they can heal lacerations without forming scar tissue, heal internal organs and regrow spinal tissue. Subsequently, scientists want to figure out what exactly gives these salamanders their healing abilities.
A team of scientists has sequenced the entire genome of the Mexican axolot,l and an article about their work was published by Nature. The Mexican axolotl has 32 billion base pairs in its genome, compared to human’s 3 billion base pairs. Sequencing a genome this big came with a lot of problems. According to the Max Planck Society, The Heidelberg Institute for Theoretical Studies had to create new software to sequence and analyze the genome.
The Research Institute of Molecular Pathology in Vienna is home to one of the largest axolotl colonies; they are one of the major contributors to this genome project. Analysis of the genome gave scientists some of the answers they were looking for. According to their article, they discover several genes that only exist in axolotls and similar species that when expressed assist in regenerating tissue.
Unexpectedly, a vital developmental gene, PAX3, was missing from the genome and in its place, was PAX7. According to Nature, both of these genes are critical to the growth of muscle and neural tissue. Scientists are still curious about what exactly led axolotls to evolve such incredible regenerative abilities.
