Seeking the genetic determinants of intelligence in humans has proven difficult. Several hundred gene variants together likely account for 40 to 50 percent of differences in intelligence, according to The New York Times, and it’s unclear which of these genes exerts the most influence on our IQ.
So some scientists are taking a different approach. They’re looking at “the genetics of stupidity,” as Dr. Kevin Mitchell, a neurogeneticist says. What he’s talking about are not the fixed genes we all have that make us more or less equally smart, but the mutations in those genes. “This tends to run in families, which means some of us generate and retain more mutations than others do. Among our 23,000 genes, you may carry 500 mutations while I carry 1,000,” the Times writes.