Scientists in Japan say they have taken a “significant step” in their efforts to bring back the extinct woolly mammoth, the Independent newspaper is reporting.

The mammoths died out just over 4,000 years ago, but the scientists say transplanted cells taken from the carcass of the mummified remains of one found in 2010 and transplanted into a mouse recorded positive biological activity, according to the newspaper.

“The 28,000-year-old remains of a woolly mammoth, named ‘Yuka’, were found in Siberian permafrost,” the scientists say in a paper published in the journal Nature.

The scientist were able to extract tissue samples from the remains and collected 88 nucleus-like structures from muscle sample. From there, scientists injected the structures into mouse oocytes, described as a cell in an ovary which can undergo genetic division, according to the Independent.

Following the procedure, the scientists reported a “pronucleus-like structure budded from the injected … mammoth nucleus.” However, a further cell division necessary to create a viable egg was not observed.

But "these results indicate that a part of mammoth nuclei possesses the potential for nuclear reconstitution,” the scientists wrote in the paper published by Nature.

This marks a "significant step toward bringing mammoths back from the dead," Kei Miyamoto, one of the study's authors, told Japan’s Nikkei news outlet.

"We want to move our study forward to the stage of cell division," said Miyamoto, who acknowledged that "we still have a long way to go.”