The rate of cell proliferation in the tailbud is unchanged in wnt3a/wnt8 morphants. Embryos were injected with 2 mg/ml wnt3a MO (B), 0.5 mg/ml each of wnt8 ORF1 and ORF2 MOs (C), or wnt3a, wnt8 ORF1 and wnt8 ORF2 MOs together (D), and fixed at the 4-somite stage, with uninjected embryos as the control (A). tbx6 expression was visualized with a Fast Red substrate for the color reaction, which yields a fluorescent (red) product. Anti-phosphohistone H3 antibody marks mitotic nuclei (green). To determine the mitotic index, we calculated the number of mitotic cells within the tbx6 expression domain, divided by the total number of cells within that domain. Three embryos were scored for each group of embryos. We calculated a mitotic index of 7.5 (n=1281) for wild type, 6.7 (n=1089) for wnt3a morphants, 7.5 (n=772) for wnt8 MO embryos and 6.8 (n=772) for wnt3a/wnt8 morphants.