Miten se Anneli sanoikan?

The World's No.1 Science & Technology News Service



IQ is inherited, suggests twin study


15:12 05 November 01


Genes have a very strong influence over how certain parts of our brains develop, scientists in the US and Finland have found. And the parts most influenced are those that govern our cognitive ability. In short, you inherit your IQ.

Paul Thompson at the University of California at Los Angeles and his colleagues used MRI to scan the brains of 10 pairs of identical and 10 pairs of fraternal twins. Identical twins have identical genes, whereas fraternal twins sharing on average half their genes. The twins shared environments, means researchers can separate genetic and environmental factors.

The researchers found that certain regions of the brain were highly heritable. These included language areas, known as Broca's and Wernicke's areas, and the frontal region, which, among other things, plays a huge role in cognition.

In identical twins, these areas showed a 95 to 100 per cent correlation between one twin and the other - they were essentially the same. The frontal structure, says Thompson, appears to be as highly influenced by genes as the most highly influenced trait we know of - fingerprints.

"It's extraordinary how similar they are," he says. The finding suggests that environment - their own personal experiences, what they learned in life, who they knew - played a negligible role in shaping it.

Fraternal twins were near-identical in Wernicke's area, showing about 60 to 70 per cent correlation, but were less similar in other areas, . Random pairs of people would be expected to have no correlation.


Intellectual function


The study was all the more interesting in that it found that not only was this gray matter highly heritable, but it affected overall intelligence as well. "We found that differences in frontal gray matter were significantly linked with differences in intellectual function," the authors write.

The volunteers each took a battery of tests that examined 17 separate abilities, including verbal and spatial working memory, attention tasks, verbal knowledge, motor speed and visuospatial ability.




Subscribe to New Scientist for more news and features

Related Stories


Brain regions critical in allowing us to understand another person's thoughts are revealed
29 March 2001

Divorce is written in the DNA
11 July 2001

Your ability to judge musical pitch is almost entirely inherited
8 March 2001


For more related stories
search the print edition Archive



Weblinks


Paul Thompson, UCLA

Finnish Twin Cohort Study

Nature Neuroscience

How the brain works




These tests hone in on what's known as "g", the common element measured by IQ tests. People who do well on one of these tests tend to do well on them all, says Thompson.

It is not known what exactly "g" is. But these new findings suggest that "g" is not just a statistical abstraction, but rather, that it has a biological substrate in the brain, says Robert Plomin, of the Institute of Psychiatry in London. Plomin has spent eight years looking for genes behind "g". "I'm convinced that there are genes," he says, a lot of them, each with a small effect.

Stephen Kosslyn of Harvard University in Boston questions whether "g" should really be called intelligence. "G" picks up on abilities such as being able to abstract rules or figure out how to order things according to rules. "It's the kind of intelligence you need to do well in school," he says. "Not what you need to do well in life."

Journal reference: Nature Neuroscience (DOI: 10.1038/nn758)


Alison Motluk

Tuskin Tatu Vanhanen on mitään rotuoppiaan koskevia tietoja ulkomaille levittänyt.
Eikä varmaan se kauhea kepulehdistökään.