Not only do some of these genetic “hot spots” seem to be linked to many forms of autism, but some of them have a deep and significant evolutionary history. If you trace them back in time, as Evan Eichler’s laboratory has begun to do, you can begin to glimpse the emergence of precisely the traits that distinguish humans from all other animals. “It’s kind of a crazy idea,” Eichler says, “but it’s like autism is the price we pay for having an evolved human species.”
This suggests that the extra copies of the BOLA2 gene, which predispose people to neurodevelopmental disorders like autism, must also confer some genetic benefit to the human species. Otherwise, evolutionary pressure would have scrubbed the duplications out of the genome. In other words, the same duplications that can lead to autism may also create what Eichler calls genetic “nurseries” in which new gene variants arise that enhance cognition or some other human trait.