A recent collaborative study of the genes linked with intelligence is the largest study of the brain in history. It includes 200+ scientists from 100 institutions from around the world. Their aim: “to map the human genes that boost or sabotage the brain’s resistance to a variety of mental illnesses and Alzheimer’s disease”(UCLA, 2012). A study from the group, published in 2012 in Nature Genetics, may have discovered new genes linked with IQ. According to Paul Thompson, the study’s senior author, and a professor of neurology at the David Geffen School of Medicine at UCLA: “We hunted for genes that increase your risk for a single disease that your children can inherit. We also looked for factors that cause tissue atrophy and reduce brain size, which is a biological marker for hereditary disorders like schizophrenia, bipolar disorder, depression, Alzheimer’s disease and dementia.”
The project has come to be known as project ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis). It was born from a collaborative effort from brain-imaging labs worldwide. Together, the researchers pool their brain scans and gene data in an attempt to draw inferences about which genes are responsible for which sorts of idiosyncrasies. “Our individual centers couldn’t review enough brain scans to obtain definitive results…By sharing our data with Project ENIGMA, we created a sample large enough to reveal clear patterns in genetic variation and show how these changes physically alter the brain.” Together, members of Project ENIGMA analyzed brain size and memory centers in thousands of images of MRI scans from 21,151 healthy individuals, as well as looking at their DNA (UCLA, 2012). One of their primary interest was whether or not certain genes were correlated with brain size. The study was quite wide-ranging:
When the scientists zeroed in on the DNA of people whose images showed smaller brains, they found a consistent relationship between subtle shifts in the genetic code and diminished memory centers. Furthermore, the same genes affected the brain in the same ways in people across diverse populations from Australia, North America and Europe, suggesting new molecular targets for drug development (UCLA, 2012)
The team centered on a variant of a gene known as HMGA2. This gene, the researchers believe, affects both a person’s brain size as well as their intelligence. “DNA is comprised of four bases: A, C, T and G. People whose HMGA2 gene held a letter “C” instead of “T” on that location of the gene possessed larger brains and scored more highly on standardized IQ tests”(UCLA, 2012).
University of California, Los Angeles (UCLA), Health Sciences. (2012, April 15). New genes linked to brain size, intelligence. ScienceDaily. Retrieved June 13, 2014 from www.sciencedaily.com/releases/2012/04/120415150123.htm