Scientists have decoded the genome of the axolotl, the Mexican amphibian with a Mona Lisa smile. It has 32 billion base pairs, which makes it ten times the size of the human genome, and the largest genome ever sequenced.

The axolotl, endangered in the wild, has been bred in laboratories and studied for more than 150 years. It has the remarkable capacity to regrow amputated limbs complete with bones, muscles and nerves; to heal wounds without producing scar tissue; and even to regenerate damaged internal organs.

This salamander can heal a crushed spinal cord and have it function just like it did before it was damaged. This ability, which exists to such an extent in no other animal, makes its genes of considerable interest.

Now researchers, using one genetic sequencing technique to do their analysis and then another to “proof read” it, have provided researchers with the tools to study and manipulate the genes of the axolotl. Their study appears in Nature.