Clever mice

Changing a single gene is enough to improve learning and memory, US scientists report in the journal Nature. Neurobiologist Joe Tsien, in collaboration with researchers at MIT and Washington University, found that adding a single gene to mice significantly boosted the animals' ability to solve maze tasks, learn from objects and sound in their environment and to retain that knowledge. This strain of mice, named Doogie after the teenage genius in the eponymous American television show, also retained into adulthood certain brain features of juvenile mice - which, like young humans, are believed to be better than adults at grasping large amounts of new information. The work is a breakthrough in memory research and reveals a common biochemical mechanism to be at the root of nearly all learning. A gene called NR2B appears to be the switch that controls the brain's ability to associate one event with another - the core feature of learning. Tsien had previously created mice that lacked the gene in a tiny region of the brain and showed that they had impaired learning and memory. Adding new or improved function, however, is a harder task and a more rigorous test of the gene's function.

The research showed that the enhanced learning and memory abilities of the Doogie strain of mice were the result of an over-expression of a particular protein sub-unit of the NMDA receptors in the brain. Now that the precise role of this brain protein is known, drug companies could design drugs that could improve learning and boost memory in people suffering from age-related disorders such as Alzheimer's. However, some commentators as well as the researchers themselves have brought up another possible application of the research - genetic therapy on babies to overcome inherited disorders or just boost intelligence.

Although enthusiastic about the research, British neuroscientists were dismissive about claims of enhancing intelligence. 'This is a real piece of vulgar hype from Princeton,' said Steven Rose, head of the brain and behaviour group at the Open University. 'They shouldn't do this stuff, it really is irresponsible... Human intelligence is something that develops as part of the interaction between children and the social and natural world, as they grow up. It is not something locked inside a little molecule in the head.'