BACKGROUND:

Multivariate genetic research indicates that genetic effects on diverse cognitive abilities are general rather than specific or modular. General cognitive ability (g), a key factor in learning and memory, is among the most heritable behavioural traits.

AIMS:

To give a brief overview of quantitative genetic research on g and to describe initial results from a programme of research that aims to identify genes responsible for the substantial heritability of general cognitive ability.

METHOD:

The research uses a new technique called DNA pooling, which combines DNA from individuals within a group and makes it feasible to screen thousands of DNA markers for a systematic scan of the genome for associations between DNA markers and g. Two independent samples of children with very high g scores and two control samples of children with average g scores were compared in a systematic scan of 147 markers on chromosome 4 and 66 markers on chromosome 22.

RESULTS:

Three replicated associations on chromosome 4 were identified using DNA pooling and confirmed using individual genotyping.

CONCLUSIONS:

These first results of the application of DNA pooling in systematic analysis of allelic association are encouraging.