title: Origin of major histocompatibility complex polymorphism: the trans-species hypothesis.
authors.forename: J
authors.initials: J
authors.lastname: Klein
mesh_terms: D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D004777:Environment; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D008285:Major Histocompatibility Complex; D011110:Polymorphism, Genetic; D013045:Species Specificity
chemical_list: D006680:HLA Antigens