The Rh Factor and Racial Origins

Abstract

The Rh blood factor which is inherited as a simple Mendelian dominant by a pair of allelic genes (Rh and rh) has been reported present in blood cells of 85% of white individuals, in a higher % of Negroes and in almost all of the American Indians. This racial difference in possession of this factor is explained by the probable existence of an Rh-negative race which hybridized with an Rh-positive race. No known mutation rate is high enough to account for the present number of Rh-negative individuals on that basis.