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LA Times: Intelligence is in your genes!


Occasionally the science page of a major newspaper will break with the paper’s usual politically correct fantasies and report the truth.

From LA Times Health Page…

Intelligence is in the genes, researchers reported Tuesday in the journal Molecular Psychology.

The international team, led by Ian Deary of the University of Edinburgh in Scotland and Peter Visscher of the Queensland Institute of Medical Research in Brisbane, Australia, compared the DNA of more than 3,500 people, middle aged and older, who also had taken intelligence tests. They calculated that more than 40% of the differences in intelligence among test subjects was associated with genetic variation.

The genome-wide association study, as such broad-sweep genetic studies are known, suggested that humans inherit much of their smarts, and a large number of genes are involved.

Booster Shots asked Deary to answer a few questions about the research. The following is an edited version of our questions and his emailed responses.

What exactly were you looking for when you looked at test subjects’ genetic information?

We studied over 3,500 people. We looked at over 500,000 individual locations on the chromosomal DNA where people are known to differ. We looked at the association between those DNA differences and two types of intelligence. One type of intelligence was on-the-spot thinking (fluid intelligence) and the other was vocabulary (crystallized intelligence).

You wrote in your paper that 40% of the variation in crystallized intelligence and 51% of the variation in fluid intelligence is associated with genetic differences. How did you calculate those figures? And where does the rest of intelligence come from? Other genes, or environmental factors?

To estimate the proportion of variance associated with common genetic differences (in what are called single nucleotide polymorphisms, or SNPs) we used a new genetic statistics procedure invented by Professor Visscher and his colleagues in Brisbane, called GCTA. The rest of people’s differences in those types of intelligence could come from genetic differences we were not able to capture, or from the environment.