In vitro and in silico experimental data reveal that DAN reduces neural crest cell speed. (A) Schematic representation of experiment. (B) Speed of neural crest cells grown in vitro, exposed to 0 (n = 46 cells), 1 µg/ml (n = 30 cells), and 10 µg/ml (n = 70 cells) of DAN protein. *, P < 0.013; **, P < 0.043. (C) Directionality of the same cells tracked in B. *, P < 0.0079; **, P < 0.0012. (D) BrdU incorporation as an indicator of cell proliferation when exposed to 0 (n = 7 neural tube cultures, 961 cells), 1 µg/ml (n = 8 neural tube cultures, 847 cells), and 10 µg/ml (n = 9 neural tube cultures, 980 cells). *, P = 0.016. Two-sided Student’s t test. (E) No reduction in speed: the model simulated is as in McLennan et al. (2015b) on a widened domain with cell speed 40 µm/h. Neural crest cells are shown in green, cells in a leader state are in yellow, detached trailing cells in green, and the background blue color shows VEGF chemoattractant concentration. (F) Moderate reduction in speed: inside the area representing DAN expression (red dashed rectangle), cell speed is reduced in proportion to DAN concentration (see the Computer modeling supports the hypothesis… section of Results). The minimum cell speed is 30 µm/h. (G) Modeling increased DAN: the simulation is set up as in B, but the cell speed is now reduced down to 10 µm/h (at peak concentration of DAN). (H) Migration profiles: mean cell number versus distance migrated for 10 repeated simulations as in E–G. Error bars show SEM.