Monday, April 16, 2012

Gene shown to increase brain size and intelligence

How smart you are is determined by environmental as well as genetic factors. What exactly determines our intelligence is not well understood, but a large study performed by the University of California in Las Vegas has revealed that a certain genetic variant increases brain size as well as intelligence, providing a biological foundation for smartness. In future studies, the scientists also hope to uncover genes that are associated with various brain diseases, such as Alzheimer's.

By analyzing brains of volunteers in the study while simultaneously looking for modifications in the DNA, the researchers attempted to link the two together. The study they performed was rather large, comprising of 21.151 healthy people undergoing an MRI scan and a gene check. By linking the two together, attempts were made to find out how gene variants affect brain physiology.
Setting up such a large study allowed for powerful statistical analysis, resulting in what is said to be watertight proof for a link between genes and brain size. Most striking was a common variant found in a gene called HMGA2: people with a particular form of this gene gained higher scores in IQ tests, and had, on average, larger brains. Scientists also found differences in brain areas related to learning and memory, providing a biological basis for their higher IQ scores.

One letter
Most striking about the findings is the fact that only an incredibly small difference in the HMGA2 gene structure was found in people with 'boosted' intelligence. Individual genes consist of long strings of code, written in the language of DNA, which consists of four building blocks. The string can be made from hundreds of thousands of building blocks, and the change of one building block into another made all the difference that the scientists were able to observe. It is peculiar that such a minor tweak can impact things such as intelligence and brain size in a detectable and observable way.
The four 'letters' of the DNA: A, T, C and G. They pair up and form the code or blueprints for genes.
By connecting genes and brains, scientists may be able to develop ways to stimulate our intelligence in a biological way. By finding out what HMGA2 does in our brains, therapies based on it may boost our intelligence beyond our 'normal' capabilities. Additionally, the large database that was used in the study may also help researchers find genes related to brain diseases, leading us to new treatments.

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