We’ve known for quite some time that intelligence seems to run in families.
Until recently, we did not know the specifics of any genetic cause for this link or how much is the result of the influence of nurture on an individual’s development.
An international group of researchers have now identified several key genetic variants that are associated with increased intelligence in those who have them.
A network of genes linked to increased head size and larger volume in the hippocampus (a brain structure important in learning and memory), have also shown a correlation to IQ scores—those who have this particular gene variant score a little higher on standardized IQ tests than those without it.
This finding is the strongest direct genetic link so far for intelligence and has spurred scientists to continue using the same strategy to locate more genetic variants associated with brain structure and IQ.
Twenty-four genetic variants within six genes have been identified that are associated with differences in the structural integrity of brain pathways.
In their study, the researchers measured the insulation of neural pathways and found the level of insulation affects how efficiently the brain functions and also how well it resists disease.
Although many of these genes were already known, they had not been linked to brain integrity or intelligence before.
Of course, this is very interesting as it takes us closer to understanding the genetic building blocks behind different human characteristics—but as in most things human, the presence or absence of these genes is not the only way intelligence can be gained.
Nature and nurture both play a role. A person does begin with a genetic predisposition and then our environment does much to further shape our development—in both positive and negative ways.
Even the expression of our genes is affected by our environment and nature and nurture are inextricably intertwined throughout a person’s life.
In this study, the presence of these specific genetic variants accounted for only slight increases in IQ—one or two points on average—leaving much room or other factors to contribute to intelligence.
An IQ test is also only one measure of one’s capability.
A recent study of child prodigies found that some of them had relatively normal IQ scores.
Their amazing ability could not, therefore, be accounted for by this single measure.
Memory differences were more remarkable than overall IQ.
It seemed, however, that even this could not adequately account for their performances.
And, although basic intelligence is a good quality to have, every person can work toward fulfilling his or her potential by continuing to learn new things and engage with the world.
