Scientists Discover Gene Which Causes Brain Size and Intelligence

August 2013. Nearly 100 years of leftist lies and deception, which has claimed that intelligence is not genetic, has been destroyed by the science of genetics.

According to a new study, just published in the University of California Los Angeles (UCLA) newsroom, scientists have definitively found the genes which control brain size and intelligence.

Even worse for liberals, dozens of studies have found race differences in brain size,whether measured by MRI, endocranial volume, brain weight at autopsy, or external head size (with or without corrections for body size).

Most were carried out on the three major races of East Asians, Europeans, and Africans. Averaging all the data, the following figures have emerged: Brain size average for East Asians = 1364 cubic cm; Whites = 1347 cubic cm; and Blacks = 1267 cubic cm.

The overall mean for East Asians was 17 cubic cm more than for Whites and 97 cubic cm more than for Blacks.

Since every cubic centimeter of brain tissue contains millions of brain cells and billions of synapses, the race differences in brain size help to explain the race differences in IQ.

The latest overview, billed as the “world’s largest brain study to date,”  saw a team of more than 200 scientists from 100 institutions worldwide collaborate to map the human genes that boost or sabotage the brain’s resistance to a variety of mental illnesses and Alzheimer’s disease.

Additionally, the study (also published in the journal Nature Genetics), found new genes which control “differences in brain size and intelligence.”

 “We searched for two things in this study,” said senior author Paul Thompson, professor of neurology at the David Geffen School of Medicine at UCLA and a member of the UCLA Laboratory of Neuro Imaging.

“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 disorders like schizophrenia, bipolar disorder, depression, Alzheimer’s disease and dementia.”

Three years ago, Thompson’s lab partnered with geneticists Nick Martin and Margaret Wright at the Queensland Institute for Medical Research in Brisbane, Australia, and with geneticist Barbara Franke of Radboud University Nijmegen Medical Centre in the Netherlands.

The four investigators recruited brain-imaging labs around the world to pool their brain scans and genomic data, and Project ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) was born.

“Our individual centers couldn’t review enough brain scans to obtain definitive results,” said Thompson, who is also a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA.

“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.”

In the past, neuroscientists screened the genomes of people suffering from a specific brain disease and combed their DNA to uncover a common variant.

In this study, Project ENIGMA researchers measured the size of the brain and its memory centers in thousands of MRI images from 21,151 healthy people while simultaneously screening their DNA.

“Earlier studies have uncovered risk genes for common diseases, yet it’s not always understood how these genes affect the brain,” Thompson said.

“This led our team to screen brain scans worldwide for genes that directly harm or protect the brain.”

In poring over the data, Project ENIGMA researchers explored whether any genetic variations correlated to brain size.

Project ENIGMA investigators also discovered genes that explain individual differences in intelligence. They found that a variant in a gene called HMGA2 affected brain size, as well as a person’s intelligence.

DNA comprises four bases: A (adenine), C (cytosine), T (thymine) and G (guanine). People whose HMGA2 gene held a letter “C” instead of a “T” at a specific location on the gene possessed larger brains and scored more highly on standardized IQ tests.

“This is a really exciting discovery, that a single letter change leads to a bigger brain,” Thompson said.

“We found fairly unequivocal proof supporting a genetic link to brain function and intelligence. For the first time, we have watertight evidence of how these genes affect the brain.”

 See also:

Race Differences in average IQ are largely genetic,” News-Medical.Net, April 26, 2005.

Brain size as an explanation of national differences in IQ, longevity, and other life-history variables,” J. Philippe Rushton, Personality and Individual Differences 48 (2010) 97–99.

Image: Adapted from an original produced in 2009 by “European Youth Campaign Against Racism,” supported by the Commission for Racial Equality, and created by Saatchi & Saatchi London.

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