Study: Garfish may hold secret to limb regeneration in humans

EAST LANSING, Mich — Could a freshwater fish hold the answer to limb regeneration in humans? Garfish are a bit scary looking at first glance, and often compared to dinosaurs, but it appears these fish have been hiding a major genetic secret in their fins for thousands of years. That’s because garfish, like many other reptiles and fish, have the ability to regenerate entire body parts.

Researchers at Michigan State University set out to study how exactly garfish regenerate entire fins, and discovered that humans posses the very same genes used by garfish to regenerate the endochondral bones within their fins. These fin bones are essentially the equivalent of human leg and arm bones.

“Gars are often considered ‘dinosaur fish’ because of their ancestor-resembling body type,” research leader Ingo Braasch explains in a release. “They’re becoming a popular, new research organism for biomedical research, largely in part because the gar genome is quite similar to the human genome.”

Garfish are especially interesting to the scientific community because they serve as both inspiration for innovation in the future and as a link to the past. The garfish genome is similar to both zebrafish, which are already commonly used as a genetic model for human medical breakthroughs, and the human genome. On top of all that, garfish tend to evolve slower than other fish, and have retained many ancestral elements in their genome, providing researchers with a glimpse into the past.

Braasch and his team studied how gars regenerate their fins, and located the exact genes and mechanisms that make regeneration possible. Once they compared their findings to the human genome, they discovered that the genes responsible for regeneration are also present in humans. However, somewhere along the evolutionary road, humans lost the ability to activate these genes.

“The genes responsible for this action in fish also are largely present in humans,” Braasch says. “What’s missing, though, are the genetic mechanisms that activate these genes in humans. It is likely that the genetic switches that activate the genes have been lost or altered during the evolution of mammals, including humans.”

Researchers say that continued research into these genes and missing mechanisms in humans may eventually result in medical advances that would have been considered science fiction just a few years ago.

“The more we study these commonalities among vertebrates, the more we can home in on prime targets for awakening this program for regenerative therapies in humans,” Braasch said. “Such direct biomedical advances remain in the distant future, but studies of fin regeneration in fish will continue to reveal much about the regenerative potential of vertebrates.”

The study is published in the scientific journal PNAS.