[Hypothesis of "immunological testing" of partners--systems of "friend and foe" recognition in historical prospect].

The hypothesis of "autoimmune testing" of mating partners assumes formation of individual system of perception on the basis of an immunologic principle, i.e. by lifetime selection of "direct" or "reverse casts" of own key antigens or signal molecules. Such system provides the coordinated change of signaling systems and system of their perception at formation of new adaptations that leads to automatic formation of reproductive isolation within the limited number of generations. Presence of the "friend-foe" recognition systems practically in all living organisms assumes formation of potential mating partners "autoimmune testing" mechanisms at the earliest evolution stages. In this article we analyze possible mechanisms of a "friend and foe" discrimination with MHC-proteins and their homologues in historical prospect--from bacteria to the lower Chordates.