Tracking down genes for intelligence

15 March 2010

G proteins influence cognitive skills

Recalcitrant G proteins might be the cause of lower intelligence, schizophrenia and autism. These proteins are located on the inside of each cell membrane and can pass on messages from the outside to the inside of a cell. Almost every time your brain wants to pass on a message, this switch is in the way. Vidi winner Danielle Posthuma discovered how big a role G switches play.

Up until now, nobody had really worked out which genes are responsible for intelligence. Danielle Posthuma made use of a new method to determine where the communication process between cells fails. Each time your brain wants to pass on a message to a cell, your genes must set a whole chain of proteins to work in order to reach the cell. In many different chains of proteins, a chain is like a small pathway that passes on the message, groups of proteins play the same role. For example, pathway one contains the proteins A, C, G, and K and pathway two E, F, G and L. Protein G therefore has a function in both pathways. By examining proteins which have the same function in different pathways, rather than all of the proteins along a pathway, Danielle Posthuma discovered the importance of the G proteins.

G proteins have a major controlling function

The biological psychologist investigated 627 study subjects with ADHD. All of them completed an IQ test. Posthuma and her colleagues mapped the genotype – the collection of genetically determined characteristics – of all of the study subjects. Intelligence is not dependent on a single switch in the brain and hence a single series of proteins, but rather a large number of series. Posthuma established that G proteins account for more than 3% of the variation in intelligence. As G proteins are found in many of the series, there are major consequences when they fail to function.

Posthuma also investigated more than 1000 study subjects without ADHD, and G proteins were also found to play a crucial role in them. The results of the study were recently published in the renowned journal The American Journal of Human Genetics. The method used by Posthuma – investigating groups of genes with the same function – offers many possibilities for future genetics research.

Synapses

G proteins are probably so important for intelligence because they are part of the synapses. A synapse is a space where the nerve cells connect and messages are passed on. The better the message is passed on the better your brain functions and the more intelligent you are. Earlier research had already shown that about 40 to 80% of your intelligence is determined genetically.

Vidi winner

In 2005, Danielle Posthuma received a Vidi grant from NWO's Innovational Research Incentives Scheme. This scheme is aimed at researchers who carry out challenging and groundbreaking research. In addition to her Vidi, Danielle Posthuma also received a so-called Aspasia grant from NWO. This award goes to universities who promote female Vidi and Vici laureates within one year to an associate of full professorship.

About NWO

The Netherlands Organisation for Scientific Research (NWO) is the principal Dutch science funding body and its mission is to facilitate excellent scientific research in the Netherlands by means of national competition. Each year NWO spends more than 700 million euro on grants for top researchers, on innovative instruments and equipment, and on institutes where top research is performed. NWO funds the research of more than 5300 talented researchers at universities and institutes. Independent experts select proposals by means of a peer review system. NWO facilitates the transfer of knowledge to society.

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last modified on 11 May 2010