Scientists Identify Two Genes Key To Axolotl Limb Regeneration

  The regenerative properties of axolotls has led to them become one of the most studied species of salamander in the world. In 2018 their genome, which is 10 times longer than that of humans, became the longest yet to be sequenced. However, understanding the functions of the genes associated with axolotl regeneration has proven a challenge for scientists, as they are contained within reams of repeated lengths of DNA.

Researchers at Yale University have developed a novel screening platform to potentially circumvent this problem, and bring the possibility of applying this regenerative process to humans a step closer. Their novel screening platform involved the creation of markers to track 25 of the genes suspected to be involved in axolotl limb regeneration.

“It regenerates almost anything after almost any injury that doesn’t kill it,” said Parker Flowers, co-author and Professor of Molecular, Cellular, and Developmental Biology at Yale University.

This includes limbs, spinal cords, hearts and other organs – setting them apart from other amphibians who also perform regenerative processes.

From their multi-step approach published in the journal eLIFE, the Yale researchers discovered two genes, catalase and fetuin-b, that were necessary for cell regeneration in limbs, and partial regeneration of the tail. Flowers stressed that many more such genes probably exist.

It is hoped that one day the information gathered from the axolotl genome will lead to regenerative properties applied in humans, such as in restoring damaged tissues. Last year, scientists discovered that we already have some “inner salamander” capacity to repair cartilage.

In the rare cases that axolotl's do reach adulthood, they more closely resemble their tiger salamander relatives. Jay Ondreicka/ Shutterstock

Not only do axolotl’s possess regenerative powers, but they are also neotenic; meaning that they don’t go through a period of metamorphosis like other amphibians. Therefore, they retain juvenile features such as gills, which gives them the appearance of a feathery headdress, for their 15-year lifespan.

Axotol’s inability to “grow up” also means that they only inhabit water. They are found exclusively in the lake complex of Xochimilco near Mexico City, but the demands of the densely populated capital has resulted in the contamination and draining of the lake.

Axolotl’s, also described as the Mexican walking fish, have been labeled as critically endangered since 2006. The situation could have been much worse, but having been bred for research since 1863, and their popularity as pets, the species has continued to hang on.