Molecular evolution inferred from immunological cross-reactivity of immunoglobulin G among Chiroptera and closely related species.

We examined the relationships between Megachiroptera and Microchiroptera, and between Chiroptera and other closely related species by the cross-reactivity of immunoglobulin epitopes. Rabbit polyclonal antibody to bat IgG was used for determining the cross-reactivity by a competitive ELISA method. Megachiroptera and Microchiroptera showed high cross-reactivity, over 95.3%, with each other. However, primates and insectivores showed very low cross-reactivity, 8.6 to 20.2% and 5.3 to 12.7%, respectively. These results suggest that suborders of Chiroptera are monophyletic and Chiroptera have a relatively closer relationship to primates than to insectivores.