Scientists resurrect frozen mice in cloning experiment

New cloning technology opened the door for scientists to resurrect mice using frozen cells that had been kept in a deep freeze for the past 16 years. The new approach, once thought impossible, may lead to new projects that give birth to woolly mammoths or other species that are extinct.

The Japanese scientific team gathered nuclei from the brain cells of frozen mice and injected them into empty eggs which had all DNA removed from them. Those were then used to create cloned embryos which were used to harvest stem cells for a second round of cloning.

"We have demonstrated that healthy cloned mice and chimeric clonal mice could be obtained by nuclear transfer using donor nuclei from cells obtained from bodies frozen without cryoprotectants for up to 16 years," says the team. And other sources of frozen nuclei could assist their efforts to revive extinct species.

"This would increase the chances of finding tissues in good condition. At present, the lack of suitable species for recipient oocytes (eggs) and for surrogate mothers is one of the major problems that needs to be solved for the method to be applied in extinct or endangered animals."

- read the report from the Press Association