If there were single genes that produced high intelligence scientists probably would have found one by now. Those sorts of traits are almost certainly highly po

If there were single genes that produced high intelligence scientists probably would have found one by now. Those sorts of traits are almost certainly highly polygenic. Any single gene is likely to have both small and unpredictable contributions to the traits in question. Even totting up all your "good" and "bad" genes to try to come up with a genetic score is fraught due to complicated interactions; perhaps two "good" genes interact badly and make a bad result, or similar.