Scientists clone from frozen mice

The clones were created using brain cells from frozen mice (Pic: PNAS/PA)

Japanese scientists have managed to create clones from the bodies of mice which have been frozen for 16 years.
Cloning had so far only been achieved using live donor cells and transferring their DNA to recipient eggs.
Experts believed that using thawed frozen cells would not be possible because of ice damage to the DNA.
The scientists in Kobe, Japan, said the technique raised the possibility of recreating extinct creatures such as mammoths from their frozen remains.
Every successful clone since Dolly the sheep was born in 1996 has been created by a method where the nucleus has been removed, placed in an empty egg and kick-started into replicating by chemicals or electricity.
Frozen bodies
The Japanese research suggests it is not the case that frozen cells would be unusable because the formation of ice would be likely to damage the DNA they contained.
The scientists successfully created clones using the brain cells from mice that had been frozen at -20C.
The frozen bodies of mammoths have been found dating back 40,000 years.
However, the researchers warned that the lack of suitable species for recipient eggs and surrogate mothers were "major problems" for the technique to be used for extinct or endangered animals.
The work at Kobe's Centre for Developmental Biology was reported in the journal Proceedings of the National Academy of Sciences (PNAS).