Effects of Long Term Oppression

Has anyone done any studies on the long term effects of oppression in minority populations? First to mind are, of course, African Americans, but virtually every group, Native Americans, Jews, Asian, Arabic, Hispanic, Irish, Italian - has suffered bad treatment at the hands of the majority here, but it's common around the world: Jews and Romany in Europe, Semetic northern Africans against southern black Africans, Chinese and Hindus in southeast Asia...I've even heard a person from the island of Palau badmouthing people from the island of Yap and this list is in no way complete. With all this evidence available I just wonder if any groups has examined the effects of this over generations? How are the individuals, cultures, societies affected by hate? Does being hated affect our genes. Does hating affect the genes?