Completed Axolotl Genome Could Help Regenerating Human Tissue

Scientists from the Kentucky University finished the genome sequencing of the axolotl, a salamander endemic to a very reduced lakes and canals system in the heart of Mexico, which could hold the key to regenerating human tissue.

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The axolotl, meaning water animal and often referred to as ‘Mexican walking fish,’ used to live in the Lake Texcoco when the Mexica people arrived to Mexico’s Valley and founded what would later be known as the Aztec Empire. It plays a key role in Mexican mythology and identity, being associated with deities such as Xolotl, who used to help souls reach the Mictlan.

Its ability to completely regenerate “almost everything you cut off them,” including spinal cords, eyes and parts of their brains, has fascinated scientists for years, raising interest in their medical uses.

The achievement is documented in the “Genome Research” specialized journal, published on Jan. 24. According to Randal Voss, who does research on brain and spinal cord damage at the University of Kentucky, this is the first time that the complete genome of an animal the size of an axolotl is completely sequenced and assembled. Voss says this salamander’s genome is “the best model” to study the mechanisms of body part regeneration.

Jeramiah Smith, who works at the biology department at the same university, says the axolotl’s genome is 10 times larger than a human’s, with 32 billion base pairs compared to about 3 billion.

The genome was first completed in 2018 by a European team, and their U.S. counterpart just added the sequencing of whole chromosomes, “about a thousand-fold increase in the length of assembled pieces,” Smith told the Smithsonian. Now, both teams are working together to improve the model.

The Kentucky team already identified a gene that causes a heart defect typical of the species, causing the organ to not develop properly during its early life. The finding could shed some light on the human’s own heart problems.

The axolotl is easily bred in laboratories and has been the subject of investigations since Alexander von Humboldt collected a especimen during his time in Mexico. The University of Kentucky is the only place in the U.S. that works with the animal, having about 1,000 adults, and provides specimens to researchers around the world.

It was declared critically endangered in 2006 as its natural habitat has been decimated by the expansion of Mexico City, which replaced Tenochtitlan after the European conquest. Now, what’s left of Lake Texcoco is called Lake Xochimilco, a small fraction of the original waterbody located in Mexico City’s southeast.

The remaining lake and canals are a popular tourist attraction, with its picturesque views, where people rent small boats called ‘trajineras’ to have a quiet tour or a full party with music and alcohol. During high season and weekends, the canals can be so packed with boats that one can barely see the water.