I know its been a few months but I am new to the forum and just ran across your question.... RH Positive blood is decended from the Rhese Monkey, which is supposed to be where are genetic markers lie or where we evolved. RH Negative blood has no traces of this monkey and therefore many people speculate that it identifies us with another species otherworldly or just another species that has not yet been identified. I know its not much but I hope it helps.