Smarter GM mice enter a moral maze

Scientists have shown intelligence can be improved by genetic engineering - at least in laboratory mice.

Scientists have shown intelligence can be improved by genetic engineering - at least in laboratory mice.

The researchers found that altering a gene involved in the production of a key growth factor in the brain improved the ability of the animals to find their way out of a complicated maze.

Ethical objections to the genetic manipulation of human embryos prevents similar experiments on people but the study is likely to help scientists in the field to understand better the development of the human brain.

Aryeh Routtenberg, a neuroscientist at the Northwestern University in Evanston, Illinois, demonstrated that super-intelligent mice could be created by manipulating a gene called GAP-43, which controls the production of a protein that stimulates the growth of nerve cells in the brain.

The study, published in the Proceedings of the National Academy of Sciences, builds on the results of experiments last year showing that other kinds of genetic manipulation can improve the abilities of laboratory mice to find their way out of a maze. The latest findings demonstrate that the murine genes, which are also found in humans performing similar functions, play a decisive role in determining the differences between the behavioural abilities of mice.

Genetically manipulated mice have GAP-43 genes that go into overdrive, producing excess growth factors in the brain and stimulating a greater number of connections between nerve cells.

"In the past 25 years, candidate growth genes have been implicated in learning processes, but it has not been demonstrated that they in fact enhance them," Dr Routtenberg and his colleagues report.

"Genetic overexpression of the growth-associated protein GAP-43 ... dramatically enhanced learning."

The genetically engineered mice were significantly more likely to remember a route out of the maze as well as learning more quickly how to escape, the researchers found.