A team of scientists believes it can potentially recreate giant mammoths using cloning techniques.
The Japanese scientists said they have been able to clone mice which have been frozen for 16 years.
The experts ]said their techniques raised the possibility of recreating extinct creatures, such as mammoth, from their frozen remains.
Many of the successful clones since Dolly the sheep was born in 1996 have been created by a method where the nucleus of a cell has been removed, placed in an empty egg and kick-started into replicating by chemicals or electricity.
It is not the only cloning technique, and Australian researchers reported cloning a pig in 2001 from cells that had been frozen for two years. The Adelaide-based team said its cloning method differed from the Dolly approach in important respects.
The Japanese research was undertaken at Kobe's Centre for Developmental Biology and is reported in the journal Proceedings of the National Academy of Sciences.
The work extends the time frozen material can be held before it is used to clone an animal.
The scientists said they created their mice from the brain cells of rodents that had been kept in laboratory conditions at -20C
