ABSTRACT
Though people like to think of culture, language and religion as barriers between groups; history is full of religious conversions, intermarriages, illegitimate births and adoptions across those lines. One ancestral link to another cultural group among your millions of forebears, and you share ancestors with everyone in that group. So, as long as they had children, everyone who reproduced with somebody who was born far from their own natal home helped weave the tight web of brotherhood we all share.
