Understand The Times, International

The cells from a human foetus have been injected into baby mice to create animals which have brains that are half human. Researchers at the University of Rochester Medical said it was like �ramping up the power� of the mouse brain, because human cells are so much more advanced.

They found that mice with the human brain cells had memories that were four times better than their siblings who did not have the injections. �We can say they were significantly smarter than control mice,� said lead researcher Professor Steve Goldman told New Scientist magazine.

�These were whopping effects.�

The goal was not to create a new species of �supermouse� but rather to make the brains of mice more humanlike so that scientists can advance their understanding of brain disease. The team created the hybrid mice by injecting �glial� cells from donated human foetuses � left over from IVF � into mouse pups.

Scientists found that within a year of the injections the human cells had taken over with the mouse cells �fleeing to the margins.� �It�s like ramping up the power of your computer,� added Prof Goldman.

Although Professor Goldman said that the cells did not make the mice �more human� he admitted that the team had stopped short at injecting the cells into monkeys.
�We briefly considered it buy decided not to because of all the potential ethical issues,� added Prof Goldman.

Other experts said it was astonishing that such a huge effect could be seen with just a simple injection of human cells. "That the cells work at all in a different species is amazing and poses the question of which properties are being driven by the cell itself and which is by the new environment,� said Prof Wolfgang Enard, of Ludwig Maximilian University of Munich. But he added: �If you make animals more human-like where do you stop?�

December 4 - Human foetus cells injected into baby mice to create �supermouse�