Figure 3: Symmetric and asymmetric division of S. aurata radial-glial cells (RDGs). (a) Phase contrast image showing symmetric divisions with vertical cleavages resulting only in neuronal production of daughter cells similar in shape. (b) Phase contrast image showing asymmetric divisions with horizontal cleavages by generating one new radial glial cell and one neuron progenitor (cell/cell). The bracketed area in (c) is shown in separate picture in (c’) and (c”), as inverted phase contrast image displaying asymmetric division. Arrowheads in red indicate the horizontal cleavage plane generating the asymmetric RG cell division, white dotted lines indicate RG fibers, red circles indicate the neuron progenitor. (d) Phase contrast image showing asymmetric divisions on horizontal cleavage resulting in one radial fiber and one neuron progenitor (fiber/cell). Particularly (f) at the fiber extremity grows a thick process which collapses, generating a neuron that began to develop a line of newborn neurons by symmetric divisions. (e) DAPI counterstained nuclei show asymmetric divisions with horizontal cleavages