'Extinct' Fish DNA Makes Mice Grow Limbs When Injected

18/04/2013 11:17 BST | Updated 18/04/2013 11:19 BST

In what sounds like an early failed Jurassic Park experiment, scientists have made mice sprout limbs by implanting them with DNA from a fish that was once thought to be extinct.

The strange experiment could have ramifications for many fields, and could shed light on how four-legged animals - tetrapods - evolved from fish.

The DNA was from a coelacanth - a pre-historic fish from the Cretaceous period 145 to 66 million years ago.


The first living coelacanths were found near the Comoros Islands in the Indian Ocean

Until 1938 the fish was assumed to have been extinct for millions of years, as the only specimens were long dead fossils.

But a closely related cousin of the coelacanth, the lungfish, has long fascinated scientists since it breathes air - a crucial step in the evolution of tetrapods.

Unfortunately its DNA is too large to crack, while coelacanth DNA is similar and far shorter.

Dr Chris Amemiya, a biologist at the University of Washington in Seattle, along with experts from Broad Institute of Harvard and MIT, examined coelacanth DNA for genes that could have prompted the switch to dry land.

They found a section of DNA that enhances the formation of limbs in coelacanth embryos, something found in tetrapods but not other fish.

When injected into mice the enhancer encouraged DNA to form a limb.

Palaeontologist, Dr Shubin, said: "It lit up right away and made an almost normal limb," reports the New York Times.

Much more research is needed to discover the full process of tetrapod evolution but this research is a huge step.

Scott Edwards, an evolutionary biologist at Harvard University not involved in the study, told Yahoo!: "The genome really sets a path forward for the next 10 or 20 years.