Almost all human traits are partly heritable. That’s been known for decades. But until a few years ago, no one knew what specific bits of DNA code determine any given trait. Now, however, geneticists have identified at least a few hundred variants in the DNA code that are statistically associated with important traits such as intelligence, depression and risk tolerance. Over the next decade, they are on track to identify thousands of variants associated with dozens of traits. That achievement will open up the ability to score genetic potential on those traits and thereby revolutionize the social sciences.
The methods of scoring are improving almost monthly, but the essence is simple. Each variant has a version (more precisely, one of the alleles in a single nucleotide polymorphism) associated with a small boost to the trait in question. If you add up those small boosts, you have a score for that trait, in the same sense that you have an IQ score if you add up all the correct answers to the questions on an IQ test. In the case of DNA variants, it is called a “polygenic score.”
