Cross-reactivity between immunoglobulin G antibodies of whales and dolphins correlates with evolutionary distance

Growing morphological and molecular evidence indicates that the porpoises, dolphins, and whales evolvedwithin the even-toed ungulates, formerly known as Artiodactyla. These animals are now grouped in theCetartiodactyla. We evaluated the antigenic similarity of the immunoglobulin G (IgG) molecules of 15 cetaceanspecies and the domestic cow. The similarity was scored using three distinct antibodies raised againstbottlenose dolphin (Tursiops truncatus) IgG in a Western blot, an indirect enzyme-linked immunosorbent assay(ELISA), and a competitive ELISA format. A score was generated for the genetic distance between each speciesand T. truncatus using the cytochrome b sequence. Each antibody displayed a distinct pattern of reactivity withthe IgG antibodies of the various species.