Cumulative displacement along anterior-posterior axis of apical or basal side of CD8-GFP labeled clones of cells that were initially located in AC region as they moved into MF and P region, separated for prospective photoreceptor (PR) and non-photoreceptor (N) cells. Photoreceptor cells were identified by tracking cells back in time. Initial position of a cell is defined by position it had 200 min before entering MF region. Vertical dotted lines indicate time at which tracked cells entered MF or P region. For comparison, black line indicates displacement of center of morphogenetic furrow as viewed from apical side. Positive values indicate toward anterior, negative toward posterior. Mean and SEM are shown.n= 5 eye discs (5 PR clones, 5 N clones).