Apparently there used to be white and yellow chinese, but the yellow colored chinese were much hardier and due to natural selection over the years only the Yellow skinned chinese were left.
http://books.google.com/books?id=FC...=popular science&pg=PA403#v=onepage&q&f=false
http://books.google.com/books?id=FC...=popular science&pg=PA403#v=onepage&q&f=false