Patterns of cell movement in paraxial mesoderm. Patterns of cell movement in paraxial mesoderm. Tracks of individual cell movements over a 4 hour period in the WT region 1 (A), WT region 2 (B), WT region 3 (C) and tracks that represent cells in both regions 2 and 3 of Ptk7 mutant embryos (D). Diagrams at the end of each row indicate the specific regions of the embryo from which these images were taken (purple). Scale bar: 50 μm. Anterior is up; PNC, posterior notochord. (E) Diagram of the positions of individual labeled cells in WT and Ptk7 mutant embryos at the start and end of a 1 hour interval in a time-lapse sequence. (F) Schematic representing movements of cells in the primitive streak (blue), transitional (purple) and presomitic (orange) regions of WT and Ptk7 mutant embryos. Anterior is up. Wei Wei Yen et al. Development 2009;136:2039-2048 © 2009.