EDIT: As a general statement (Please argue logically I am interested in the counterarguement):
Some how over thousands of years of almost complete separation, people managed to genetically grow different facial structures but stayed completely the same on the inside? So only physical characteristics are heritable? That's how evolution works?
The whole tenant of evolution is that great effective genes are passed on and reflected in offspring. By arguing that there is no genetic difference you are arguing that IQ cannot be passed on and that different environments did not select for and need different levels of IQ. If you are arguing that, then you are denying evolution as a theory.