These species have highly conserved Gjd2(Cx36)/gjd1a(cx34.1)/gjd1b(cx34.7)/gjd2a(cx35.5)/gjd2b(cx35.1) proteins (mouse 98%, zebrafish 70–83%; see Fig. 1) and are well-established animal models for genetic diseases. Here, GJD2 is linked to hereditary disease.