However, genetic differences between certain groups of people can be quite significant. Sometimes, they are clustered geographically, like immunity against malaria. Other times, they are clustered based on a shared history and selection pressure, like the Jews. Or math professors.

Afterall, humans came from the same small genetic stock, and races generally reflect adaptation/mutation to particular geographies - not to the very recent economic developments.

Not to mention that diversity and specialization is generally good for trade.