If you do a search for (Average IQ by country) anyone can clearly see that there are large differences. Many Middle East and African countries have very low average IQs. Of course there are bright people on the upper end of the curve, but the averages show that the majority of the people will never advance beyond menial skill labor occupations. It should also be noted that low IQ is not the same thing as evil conduct which may have a much qreater impact by nurture.
I heard just a month ago that Appalachia did not have access to iodine and that influenced IQ