On Jan. 24, 2018, a team of researchers led by scientists in Vienna, Dresden and Heidelberg announced they had decoded the entire genetic information of the Mexican salamander axolotl. The axolotl genome, which is the largest genome ever to be sequenced, will be a powerful tool to study the molecular basis for regrowing limbs and other forms of regeneration.

Salamanders have long served as valuable biological models for developmental, regeneration and evolutionary studies. In particular, the Mexican axolotl Ambystoma mexicanum has received special attention due to its astounding ability to regenerate body-parts. If the cannibalistically inclined animal loses a limb, it will regrow a perfect substitute within weeks, complete with bones, muscles and nerves in the right places. Even more fascinating, the axolotl can repair severed spinal cord and retinal tissue.

Using the PacBio-platform, a total of 72 435 954 reads were sequenced at the DRESDEN Concept Genome Center. The analysis of the assembled genome discovered several features that seem to point to the uniqueness of the axolotl: The researchers found that several genes that only exist in axolotl and other amphibian species are expressed in regenerating limb tissue. Most strikingly, an essential developmental gene named PAX3 is completely missing from the genome, and its functions have been taken over by another gene termed PAX7. Both genes play key roles in muscle and neural development.

The sequence of the axolotl genome that is now publicly available is a powerful resource for researchers worldwide to study tissue-regeneration.