Ethnic genetic interests: do they exist, and did they evolve?

The debate over Frank Salter's work on ethnic genetic interests is flaring up over at Gene Expression in response to a post by David B. criticizing Salter's work. Here is a small contribution to put the debate in its proper perspective:

There are two components to the 'ethnic genetic interests' problem.

#1: Is it adaptive to prefer co-ethnics to foreigners?
#2: Did we evolve to prefer co-ethnics to foreigners?

The answer to #1 is probably yes, provided that we don't sacrifice too much of our personal and close family fitness in the process.

If, for example there are two ethnic groups A, B each of which controls equal amounts of equal-quality land. If A allows immigration from B, but B does not allow immigration from A, then the distinctive genes of A may end up having a percentage of only e.g., 30% in the joint population, since the members of B will fill their own land to its carrying capacity, and also use some of the resources of the land of A by migrating there.

Therefore, a politician from B who enacted such a policy would do a great benefit to his 'distinctive genes'

The answer to #2 is probably no, because unlike members of our own family which are both close to us and highly valuable, members of our ethnic group are much less valuable and distant from us. The opportunity for any 'ethnic nepotism' gene to evolve would thus be miniscule, since it could only evolve by providing dramatic benefits to many co-ethnics, and the opportunity for such dramatic actions would be lacking for the vast majority of the population.