Scientists trying to resurrect the woolly mammoth reckon they are just a couple of years away from creating a hybrid embryo.
If they manage it, it will be a huge turning point in plans to bring back the ancient beast from extinction by programming its key features into an Asian elephant.
The bundle of cells would include the genes for long shaggy hair, thick layers of fat and cold-adapted blood.
And the plan by the ambitious US scientists is to grow the mammoth inside an artificial womb rather than have a surrogate female elephant carry it.
But there are still years more work ahead before any serious attempt can be made to produce an actual living creature.
Since starting the project in 2015 the researchers have increased the number of “edits” where mammoth DNA has been spliced into the elephant genome from 15 to 45.
Professor George Church, who heads the Harvard University team, said: “We’re working on ways to evaluate the impact of all these 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.”
The woolly mammoth once roamed across Europe, Asia, Africa and North America during the last Ice Age and vanished some 4,500 years ago, probably due to a combination of climate change and hunting by humans.
Their closest living relative is the Asian – not the African – elephant.
