FIG. 5. Quantitative measurements of cluster velocity.

A: cluster velocity measurements in the lymphocyte system; figure adapted from [8] with permission of Elsevier. Top is frames from experimental movie, bottom velocity of clusters as a function of area. Data is presented for three gradient strengths (0–25, 0–100, and 0–500 ng/ml). Green line indicates minimal tug-of-war model. B: cluster velocity measurement in the border cell cluster in the Drosophila egg chamber, adapted from [55]. Top is illustration of the border cell geometry, bottom velocity as a function of cluster size; note cluster diameter is plotted here, in comparison to cluster area in A. Circles are small clusters derived from E-cadherin knockdown, squares are wild-type, and diamonds are a variety of mutants that create extralarge clusters. Solid line: fit to full theory including confinement. Dashed black line: that theory shown without the effect of confinement. Dashed red line: fit to data excluding wild-type clusters.