The Precision of Histocompatibility Response in Clonal Recognition in Tropical Marine Sponges.

Recently discovered histocompatibility-like phenomena in sponges (Phylum Porifera) have prompted attempts to measure the precision with which allogeneic grafts are recognized and rejected. The results of these investigations have been extremely varied, ranging from suggestions that allorecognition does not occur to suggestions that every genetically distinct individual may be unique in histocompatibility type. Interpretation of these findings is complicated by the variation in methods and species used by different workers. Here we compare various measurements of allorecognition precision for several species of tropical marine sponges. From our results we conclude that 1) tissue implant grafts are more prone to artifact than grafts between intact sponges; 2) the possibility of clonal propogation should be considered when graft acceptances are observed between sponges selected from a single population; and 3) allozyme variation in Niphates erecta shows that occasional grafts between genetically different individuals may be accepted.