In a study published yesterday, scientists revitalized 28,000-year-old cells from the extinct woolly mammoth. The team of Japanese and Russian researchers inserted muscle cell nuclei from a mammoth carcass into mouse ova, where they saw the cells show "signs of biological activity”—an achievement that could be the first step in creating a clone of the extinct creature.
Yuka, the mammoth from which the cells came, was discovered in Siberia's permafrost in 2010 and is regarded as one of the best-preserved mammoths ever found.
The team had initially tried to use nuclear transfer to awaken cells from a different, 15,000-year-old mammoth but were unsuccessful, “possibly owing to the technological limitations at that time and the inappropriate state of the frozen mammoth tissues,” they wrote in their first study. But the discovery of the well-preserved Yuka allowed the researchers to perform another experiment.
In the study published Monday in Scientific Reports, the scientists collected 88 nucleus-like structures from a small tissue sample. They inserted them into mouse oocytes—the cell in the ovary that can develop an ovum—and observed signs of life within the cells. “The mammoth nuclei showed the spindle assembly, histone incorporation and partial nuclear formation; however, the full activation of nuclei for cleavage was not confirmed,” the authors wrote. Although the cells did not divide and multiply, the results provide crucial information for researchers in the field.