Genetic structure of two species of Montipora on a patch reef: conflicting results from electrophoresis and histocompatibility

Spatial patterns of graft acceptance and rejection were different for two species of the coral Montipora from Kaneohe Bay, Hawaii. Electrophoretically distinct tissues were capable of fusing, indicating that clonal identity is not necessarily inferred by acceptance of grafts. For M. dilatata, 18 of 40 cases of fusion were between dissimilar genotypes and for M. verrucosa, 3 of 7 cases. In one case, fusion occurred between genotypes which shared no alleles. A greater understanding of the genetics of invertebrate immunology is required before histocompatibility criteria can be used independently to assess population genetic structure with confidence.