Seeking Superpowers in the Axolotl Genome

Seeking Superpowers in the Axolotl Genome

The axolotl, sometimes called the Mexican walking fish, is a cheerful tube sock with four legs, a crown of feathery gills and a long, tapered tail fin. It can be pale pink, golden, gray or black, speckled or not, with a countenance resembling the “slightly smiling face” emoji. Unusual among amphibians for not undergoing metamorphosis, it reaches sexual maturity and spends its life as a giant tadpole baby.

According to Aztec legend, the first of these smiling salamanders was a god who transformed himself to avoid sacrifice. Today, wild axolotls face an uncertain future. Threatened by habitat degradation and imported fish, they can only be found in the canals of Lake Xochimilco, in the far south of Mexico City.

Captive axolotls, however, are thriving in labs around the world. In a paper published Thursday in Genome Research, a team of researchers has reported the most complete assembly of DNA yet for the striking amphibians. Their work paves the way for advances in human regenerative medicine.

[Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.]

Many animals can perform some degree of regeneration, but axolotls seem almost limitless in their capabilities. As long as you don’t cut off their heads, they can “grow back a nearly perfect replica” of just about any body part, including up to half of their brain, said Jeramiah Smith, an associate professor of biology at the University of Kentucky and an author of the paper. To understand how they evolved these healing superpowers, Dr. Smith and his colleagues looked to the axolotl’s DNA.

It was like “putting together 14 linear puzzles,” said Randal Voss, a professor of neuroscience at the University of Kentucky and an author of the study.

In the process of validating their results, they identified a gene mutation that causes a commonly studied heart defect in axolotls, demonstrating that their research will speed up the process of scanning the axolotl genome for mutations in the future.

Ultimately, knowing how DNA is positioned along chromosomes “allows you to start thinking about functions and how genes are regulated,” Dr. Voss said. For instance, much of the genome consists of noncoding DNA sequences that turn genes on and off. Often, these noncoding sequences occur on the same chromosome as the genes they interact with.

“Once these relationships are known, then we can ask questions about whether the same kind of controls happen in other animals, like humans,” said Jessica Whited, a professor and limb regeneration expert at Harvard Medical School who was not involved in the study.

Over all, she added, that will help scientists understand whether there are predictable ways to “render humans more like axolotls,” fantastic regenerators of the animal kingdom.

Source link