Fig. 3

a Cell proliferation in emu limb buds at HH stage 23. Transverse sections. The apical ectodermal ridge (AER) is indicated by a white arrow in DAPI-stained sections. Green PH3 expression (a marker of cell proliferation); red PAX7 expression. In the emu forelimb bud, PAX7+ cells migrate as a cloud, while those in the hindlimb bud migrate into distinct domains. Bar 100 µm. b Quantification if cell proliferation. Mean number of PH3⁺ cells as a percentage of total DAPI⁺ cells in forelimb versus hindlimb buds over stages 19, 21 and 23. Cells were counted using Fiji software over several randomly sampled transverse sections. Data show mean ± SEM, n = seven (**p < 0.01; ns not significant)