If you go to one of the "trace your ancestry web sites," many of these sites now allow you to mail in a DNA sample, and they can trace your ancestry to different parts of the world, down to specific regions within specific countries. For example, in Europe alone, the site Ancestry.com claims they can estimate your ancestry from within 1765 regions of just Europe alone, plus all the other continents, countries and many of their regions. It appears shallow regional differences can appear on human DNA in a relativity short period of time.
Ethnicity Estimate | Next-generation AncestryDNA®
This brings up the question, if regional ethnic bits and pieces, can appear on our DNA, in a short period of time and linger to be seen centuries later, how about things like religions, that have been the central feature of all civilizations for thousands of years. Do we have religious genes on our human DNA? Would hate of religions. therefore be similar to being a racist, if religions have genes similar to race and ethnicity? These genes would impact behavior such as an enhanced imagination.
This could explain how many similar features appear in religions, over time, from regionally unrelated cultures. Christianity, for example, has many features from a common religious ancestry; part of the evolution of neural behavioral coding.
In the middle East, where the Muslim religion is still a strong central feature of many cultures, and behavior for selective advantage in culture is based on religion, this is very similar to selective behavior in any given ecosystem. There are also selective disadvantages that are enforced to speed up the process of coding. This may be good place to see how fast the DNA can change or reach a steady state. It also means ethnicity may not be fixed, but a moving target; speed of change. This speed may only apply to humans, since we have will and choice, and therefore can game natural selection with what can be called willful human selection and willful human selective advantages.