Immunoglobulin allotypes (GM and KM) indicate multiple founding populations of Native Americans: evidence of at least four migrations to the New World.

On the basis of GM and KM typing and language, approximately 28,000 Amerindians were divided into 4 groups of populations: non-Nadene South American (8 groups), non-Nadene North American (7 groups), Nadene (4 groups), and Eskaleuts (6 groups). These groups were compared to four groups of Asian populations. The distribution of GM haplotypes differed significantly among and within these groups as measured by chi-square analysis. Furthermore, as reflected in a maximum linkage cluster analysis, Amerindian populations in general cluster along geographic divisions, with Eskaleuts and Nadenes clustering with the Asian populations and non-Nadene North American and non-Nadene South American populations forming two additional clusters. Based on GM haplotype data and other genetic polymorphisms, the divisions appear to reflect populations that entered the New World at different times. It appears that the South American non-Nadene populations are the oldest, characterized by the haplotypes GMA G and GMX G, whereas later North American non-Nadene populations are characterized by high frequencies of GMA G and low frequencies of GMX G and GMA T. In contrast, Eskaleuts appear to have only GMA G and GMA T. The Nadene speakers have GMX G and GM*A T in higher and approximately equal frequencies. Maximum linkage cluster analysis places the Alaskan Athapaskans closest to northwestern Siberian populations and the Eskaleuts closest to the Chukchi, their closest Asian neighbor. These analyses, when combined with other data, suggest that, in the peopling of the New World, at least four separate migrant groups crossed Beringia at various times. It appears likely that the South American non-Nadene entered the New World before 17,000 years B.P. and that the North American non-Nadene entered in the immediate postglacial period, with the Eskaleut and Nadene arriving at a later date.