axolotl originals

Early development reveals axolotl mysteries

In the amphibian world, the axolotl is the replacement-parts king.                       

This endangered Mexican salamander serves as its own NAPA store for lost body parts, able to fully regenerate limbs, tail, heart, spine and eyes—making it a model of curiosity for regenerative biologists.

Most of the scientific focus to date has been on trained on the blastema, a remarkable cluster of cells that forms at the base of an amputated limb or damaged tissue and is the modus operandi for regeneration. It somehow coordinates a symphony of instructions to re-grow muscle, cartilage, bone, blood vessels, skin—all at the right place and right time to make a good-as-new limb.

But scientists with the Morgridge Institute for Research regenerative biology team shifted attention to the axolotl’s embryonic origins for new clues to the creature’s rare skills. In work published in the summer of 2016 in the journal Developmental Biology, researchers looked at 17 different development stages of axolotl embryos and found a highly unusual series of bursts in changes in gene expression, followed by stable periods, that is unique in developmental biology.

These “waves and troughs” of genetic change appear three times: When the genome is first activated, during formation of the early gut and during formation of the nervous system. This pattern gives scientists three hot targets for comparison to the existing bank of information on mature axolotl limb regeneration.

The axolotl, a remarkable model organism capable of complete limb and organ regeneration. Credit: Morgridge Institute for Research