The source of intelligence

2002-05-23 09:36

London - Like it or not, the human race may owe its intelligence to women, especially our female ancestors who had the good sense to chose brains over brawn in selecting the best mates.

"Humanity should be grateful, men especially," New Scientist magazine said on Wednesday.

The theory that mothers are more likely to pass on their mental ability to their offspring than fathers and that intelligence genes are concentrated on the X chromosome is not new.

It was suggested by American scientist Robert Lehrke 30 years ago, but German scientists think they have narrowed down the search for the genes.

Horst Hameister, Ulrich Zechner and their colleagues at the University of Ulm in Germany first looked at genes linked to mental impairment and found that a preponderance of them is found on the X chromosome. Females have two X chromosomes and males have an X and a Y.

Some of the genes they pinpointed have been associated with the formation of nerve endings in the brain and memory and others are thought to contribute to intelligence in their natural form.

"Most geneticists believe the German team have uncovered a real effect - an excess of X-linked genes responsible for intelligence, known in genetic parlance as the large X-chromosome effect," the magazine said.

"Many...are also convinced that this is the result of female choice," it added.