title: Many questions (and almost no answers) about the phylogenetic origin of the major histocompatibility complex.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D005075:Biological Evolution; D002875:Chromosomes; D003165:Complement System Proteins / Q000378:metabolism; D005796:Genes; D006648:Histocompatibility; D007109:Immunity; D007136:Immunoglobulins / Q000378:metabolism; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology; D010802:Phylogeny; D013045:Species Specificity; D014184:Transplantation, Homologous
chemical_list: D007136:Immunoglobulins; D003165:Complement System Proteins