'Intelligence genes' reveal their complexity - being-human - 29 November 2007 - New Scientist

'Intelligence genes' reveal their complexity - being-human - 29 November 2007 - New Scientist: "Something as subtle and complex as intelligence was never going to be pinned on just a handful of genes, as a huge trawl across the human genome seems to confirm. Although it did turn up hundreds of genes that make a contribution, their individual effects are so small that for the most part they are barely detectable. This does not mean, however, that intelligence is not inherited. The research, led by Robert Plomin of the Institute of Psychiatry in London, identified six genes that were strongly associated with high or low intelligence, but even the most powerful of these accounted for just 0.4 per cent of the variation in intelligence between individuals. The six together accounted for about 1 per cent of the variation in intelligence. Dozens of previous studies on twins and adopted children have established that about half of the variation in intelligence is down to environment, ..."