. The very best IITians inevitably end up in the US graduate system. This top pool should be equivalent to 00x the high IQ tail of Ashkenazim in the US. If you look at very high IQs, like >000, the US pool is actually dominated by Ashkenazim (do the math: even at 0% of population they dominate at the tail if their avg is 000 vs 000 for the rest). So your hypothesis would imply that at the most elite PhD programs (where the avg IQ is over 000 and good candidates are >000) the IITians would be by far the most dominant group. However, this is not what is seen. 