Why Asians are so short (perhaps)

A few days ago I posted on a gene, HMGA2, which seems to be implicated in a small proportion of the normal human variation in height. There seems to be an SNP which comes in two flavors which results in a different in height in an additive & independent manner. A friend of mine pointed out that this SNP exhibits different frequencies in different populations. The "short" allele, which tends to have an average effect of decreasing the expectation in height, is the derived form. That is, it is a newer mutant in relation to the ancestral "tall" allele. Second, it seems that it is extant at a much higher frequency in East Asians than amongst Europeans and Africans. I won't repeat the evolutionary speculations I offered in my previous post, but it seems clear that small chunks of data such as this will be fertile seed for future conjecture and model building.