A plan to revive the mammoth is on track, scientists have said after creating a new species: the woolly mouse.

Scientists at the US biotechnology company Colossal Biosciences plan to “de-extinct” the prehistoric pachyderms by genetically modifying Asian elephants to give them woolly mammoth traits. They hope the first calf will be born by the end of 2028.

Ben Lamm, co-founder and chief executive of Colossal, said the team had been studying ancient mammoth genomes and comparing them with those of Asian elephants to understand how they differ and had already begun genome-editing cells of the latter.

Now the team say they have fresh support for their approach after creating healthy, genetically modified mice that have traits geared towards cold tolerance, including woolly hair. “It does not accelerate anything but it’s a massive validating point,” Lamm said.

In the research, which has not yet been peer-reviewed, the team used a number of genome editing techniques to either genetically modify fertilised mouse eggs or modify embryonic mouse stem cells and inject them into mouse embryos, before implanting them into surrogates.

The team focused on disrupting nine genes associated with hair colour, texture, length or pattern or hair follicles. Most of these genes were selected because they were already known to influence the coats of mice, with the induced disruptions expected to produce physical traits similar to those seen in mammoths, such as golden hair.

However, two of the genes targeted in the mice were also found in mammoths, where they are thought to have contributed to