The rabbitCD1 and the evolutionary conservation of theCD1 gene family

Abstract
A comparison of the genes encoding the CD1 leucocyte differentiation antigens in man and mouse shows important differences which prompted us to analyze theCD1 genes of the rabbit. We have found that the rabbit genome contains multipleCD1 loci. Upon cloning and sequencing, one of these loci was found to encode the known rabbit CD1-like antigen (R-Ta) and to be closely related to the humanCD1b gene, which is absent in the mouse, while a second rabbit gene is closely related to both the humanR3 and the mouseCD1 genes. The data reinforce the notion of the existence of two classes ofCD1 genes, one of which is conserved in all species, while the other, albeit also evolutionarily old, has been deleted in mice as well as in other rodents.