Fig. 2

Leader identification and tip cell overtaking in the contact inhibition and cell elongation model. Sprouts formed from a spheroid in 30,000 MCS by (a) the contact inhibition model and by (b) the cell elongation model. Red cells at the sprout tips indicate the identified leader cells. Tip cell overtaking occurs in the (c) contact inhibition model as well as in (d) the cell elongation model. Two images of the same sprouts are shown for each model, with the lower sprout being at a later time point than the upper sprout. The center of mass is depicted with a colored dot for each cell and the displacement of the leader cells in time is visualized with the arrows. The mean tip cell overtake rate per sprout, calculated over 15 independent stochastic simulations, is 0.67 (±1.32) overtakes per 20,000 MCS for the contact inhibition model and 4.59 (±5.24) overtakes per 20,000 MCS for the cell elongation model