In the 1990s Black reviewed thirty-six studies of South American Indians. Not to his surprise, he discovered that overall Indians have fewer HLA types than populations from Europe, Asia, and Africa. European populations have at least thirty-five main HLA classes, whereas Indian groups have no more than seventeen. In addition, Native American HLA profiles are dominated by an unusually small number of types. About one third of South American Indians, Black discovered, have identical or near-identical HLA profiles; for Africans the figure is one in two hundred. In South America, he estimated, the
...more
