Ivory & teak, how related are South Asians & Europeans?

The post yesterday about the deletion which results in heart disease later in life had some interesting ancestry related material. This makes sense, the genetic maps which I post on now and then ultimately have a medical rationale behind them; eliminate population structure so that you don't have spurious correlations confusing you when you try and get a fix on the genetic underpinnings of a disease. By example, consider a study with cases & controls, and individuals with the trait or disease have five times the likelihood of carrying a particular allele at a particular gene. But you look more closely, and you see that if you control for race this doesn't hold, in fact you are just picking up the fact that one population has a greater propensity for the trait or disease as well as the reality that populations differ in allele frequencies on many genes. The old ...