US scientists say they are just two years away from creating a hybrid woolly mammoth embryo using DNA from specimens found frozen in Siberian ice.

It would be the latest step in plans to bring the beast back from extinction by programming its key traits into an Asian elephant.

The scientists want to grow the creature in an artificial womb instead of using a female elephant.

The woolly mammoth lived in Africa, Asia, Europe and North America during the last Ice Age, becoming extinct about 4,500 years ago - probably due to climate change and hunting by humans.

But developments in gene editing techniques, which allow precise selection and insertion of DNA, have made its return a possibility.


Image: Woolly mammoths died out about 4,500 years ago

Professor George Church, who heads the Harvard University team, said: "We're working on ways to evaluate the impact of all these (gene) edits and basically trying to establish embryogenesis in the lab.

"The list of edits affects things that contribute to the success of elephants in cold environments.

"We already know about ones to do with small ears, sub-cutaneous fat, hair and blood, but there are others that seem to be positively selected."

He added: "Our aim is to produce a hybrid elephant/mammoth embryo.

"Actually, it would be more like an elephant with a number of mammoth traits. We're not there yet, but it could happen in a couple of years."

If the mammoths roamed free again they could even help fight global warming - by stopping the greenhouse gases that are released when tundra permafrost melts.

"They keep the tundra from thawing by punching through snow and allowing cold air to come in," said Prof Church.

"In the summer they knock down trees and help the grass grow."