Fig. 4

Cell dynamics during epiboly (Wourms’ stages 18–19). When epiboly is ongoing, both green and red cells are present in dFUCCI embryos (a). As long as epiboly proceeds (b, c) the number of green EL cells gradually and slowly decreases over time, while the number of red EVL cells increases until the reaching of a plateau (graph hours 7–12). The cells in the field of view were easily tracked and counted transforming the dots in particles with IMARIS (d–f). The images and graph refer to the acquired portion of the embryos, corresponding to the superior hemisphere