This is the most comprehensive article I've read on this topic, and I loved it! That said, I want to share some family history:

I'm of mixed "race," European white and Native American (Chickasaw). My cousin Willie and I have the same genetic heritage. Yet I look 100% Nordic while he looks 100% Native American.

I've lived most of my life in typical American urban neighbohoods, while cousin Willie has chosen to stay on or near the Oklahoma reservation where my dad grew up.

I may be wrong, but I can't help but suspect it has something to do with treatment he may have been subjected to throughout his life.