Thanks for posting this.
The point about R^2 is a good one -- clearly the relative roles of variation in heritable and environment factors will depend partly on the variation in those factors in the sample being studied. The North-South Korea example is a great one for making that point.
Still, it is worth keeping in mind that the policy question that is often being asked is "if inequality in environmental factors within population Y (e.g., the United States) could somehow be eliminated, how much of the inequality in trait X (e.g, IQ) would remain." For this question, an R^2 that is valid for population Y is relevant, even if a different R^2 would be arrived at for a different population.
Thanks for summarizing and linking to the recent genome research. Not being an expert in that field at all, I would have been a little surprised if samples of 5,000 were really enough given the complexity of the genome and of human intelligence. But I suppose there could have been a few silver bullet-type genes.
