An interesting article in The Atlantic describes studies of a so-called 'orchid' gene, believed to indirectly code for a tendency to ADHD as well as anti-social behavior, violence and 'externalizing' (what we'd have called 'acting up' back in the day). The relevant evolutionary question is: If humans as both as groups and individuals generally enhance their survival chances by social cohesion, why haven't these negative alleles been selected out? Noting in passing that studies in which phenotypes are evaluated by necessarily subjective questionnaires make me twitchy, the studies cited in the article put forward a hypothesis with some experimental support: The same gene that creates the downside behavior is highly responsive, in a positive sense, to more supportive environments during childhood. It can apparently lead to either a problem child, or a super-achiever, depending.
Roughly 20% of the population have the 'orchid' allele in question. Leading me to wonder: What's the proportion of carriers in Silicon Valley in general, or in the entrepreneurial or venture capital contingents in particular? What kind of selection might be going on right under our noses?