MHC genes have been discovered in Echinodermata (Invertebrates containing 5 classes).2 classes (Ophuirids, Crinoïds) out of 5 possess HLA E, HLA B (Class I), HLADRB1, HLADQB1 (Class II). By the use of Mapping we identified 2 other MHC genes (Class II) in another Echinodermata: the sea star Asterias rubens (Asterids).