1. Harvard Medical School, New England Regional Primate Research Center, One Pine Hill Drive, Southborough, Massachusetts 01772, USA
2. ^*PO Box 9282, Guayaquil, Ecuador, South America
3. ^†Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
4. ^‡Texas A&M University, College of Veterinary Medicine, College Station, Texas 77843, USA
5. ^§ Department of Pathology, School of Medicine, University of New Mexico, New Mexico 87131, USA
6. Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, USA

Abstract

EVIDENCE suggests that the New World was colonized only 11,000–40,000 years ago by Palaeo-Indians¹. The descendants of these Palaeo-Indians therefore provide a unique opportunity to study the effects of selection on major histocompatibility complex class I genes over a short period. Here we analyse the class I alleles of the Waorani of South America and the Zuni of North America. Four of the Waorani HLA-B alleles were new functional variants which could be accounted for by intralocus recombination. In contrast, all of the Zuni HLA-A and -B molecules were present in Caucasians and orientals. This suggests that the new Waorani HLA-B variants arose in South America. The description of four new HLA-B alleles in the Waorani and another five new HLA-B alleles from two other tribes of South American Amerindians² indicates that the HLA-B locus can evolve rapidly in isolated populations. These studies underline the importance of gathering genetic data on endangered native human populations³.