LEXINGTON, Ky. — Bionic hands are no longer part of sci-fi movies and comic books. And thanks to 3D printing technology, people can now print a plastic hand. But what if we could teach our bodies to regenerate a new? Biology researchers at the University of Kentucky make this sci-fi fantasy more plausible. They assembled the complete genome of the axolotl, a unique salamander native to a lake near Mexico City.
“Axolotls have long been prized as models of regeneration,” says Randal Voss, a professor at the university’s Center for Brain and Spinal Cord Injury Research and co-principal investigator of the project, in a press release. “It’s hard to find a part of the body that they can’t regenerate: limbs, tail, spinal cord, eye and, in some species, the lens, even half of their brain regenerates.”
How do these animals relate to humans? Despite their small size and apparent simplicity, axolotls share many of the same genes as humans. Yet the axolotl has a complete set of chromosomes – a genome – that is ten times larger than that of a human.
The sheer size of the axolotl genome makes genetic analysis extremely difficult. Jeramiah Smith, associate professor in the university’s biology department and co-principal investigator, describes genetic data as a “pile of puzzle pieces”. He says getting the genome in the right order is the key to moving forward with analyzing the structure and function of the genome and uncovering “the mechanisms that give axolotls their magical powers.”
The Human Genome Project gave scientists tools to duplicate data from other organisms, but computational complications for organisms with giant genomes made the process somewhat impractical. That is until Smith and Voss got creative with genetic linkage mapping. They have developed a system to put the axolotl genome in the correct order quickly and efficiently.
It was the first genome of such a massive size to be assembled correctly.
Now that biology researchers have put this huge genome in order, they can begin to study which genes turn on and off in the regeneration process. This could eventually lead to huge implications for humans. “Just a few years ago, no one thought it was possible to assemble a genome larger than 30 GB,” Smith says. “We have now shown that it is possible to use a cost-effective and accessible method, which opens the possibility of regularly sequencing other animals with large genomes.”
Voss and Smith demonstrated this new knowledge by rapidly compiling data that identified a heart defect gene in an axolotl. Scientists say this ability has the potential to provide new models for human disease. “Biomedical research is increasingly becoming a genetics-driven enterprise,” Voss notes. “To understand human disease, you need to be able to study the functions of genes in other organisms like the axolotl.”
The university is home to approximately 1,000 adult axolotls, a resource they share with other researchers and educators around the world. With the full genome sequence in place, this population of laboratory axolotls has become even more valuable, especially given the status of these wild salamanders on the critically endangered species list.
“Now that we have access to genomic information,” Voss boasts, “we can really begin to probe the functions of axolotl genes and learn how they are able to regenerate body parts. Hopefully one day we can translate this information in human therapy, with potential applications for spinal cord injury, stroke, joint repair… the sky’s the limit, really.
The future looks bright, thanks to the regenerated eyes of the axolotl.
The research data is published in the February 2019 issue of Genome research.
This article was originally published on January 31, 2019.