Fig 4. Convergent extension through segment-specific adhesion is enhanced by a persistent migration mechanism.

(A) The ratio of the length of the long and short axis over simulation steps (MCS) without a persistence mechanism for a small and a large tissue (4x more cells). The large tissue (red curve) never reaches the same ratio as the small tissue. Next to the graph are examples of the state of both small and large tissue at the beginning and end of the simulation. Note that the cells in the small tissue actually are of the same size as those in the large tissue, but that the images are resized. J values: J _{c, m} = 12, J _{r, g} = 22, J _{r, r} = 16, γ _{r, g} = 6 (B,C) The long/short-axis ratio for the small tissue (B) or large tissue (C) with different cell speeds (indicated in the legends) resulting from different strengths of the persistence mechanism. Curves are averaged over 5 simulations, shading indicates standard deviation. Note that the speeds are emergent quantities measured from simulation output, and have dimension (lattice sites)/MCS (where the lattice sites have arbitrary length). Next to the graph are examples of the state at the end of the simulation (also with vector plots of cell displacement). The colour of the box indicates the parameter set the example belongs to. Vector plots were corrected for whole-tissue rotation, and in the plots for the large tissues, 60% of vectors were sampled for greater clarity. (B) Blue curve: μ = 0.5, s = 5; purple curve: μ = 2.0, s = 5; yellow curve: μ = 2.0, s = 10. (C) Blue curve: μ = 0.5, s = 5; purple curve: μ = 1.0, s = 10; yellow curve: μ = 1.5, s = 30. (D) The ratio of the length of the long and short axis for simulations with stiffer tissue, compared to the previous settings (large tissue). J values for stiffer tissue: J _{c, m} = 24, J _{r, g} = 44, J _{r, r} = 32, γ _{r, g} = 12. (E) Improvement of extension of the stiff tissue in the presence of persistence. Blue curve: μ = 0.5, s = 5; purple curve: μ = 2.0, s = 40; yellow curve: μ = 2.5, s = 40. (F) Example of T1 transition in a tissue with intermediate strength persistence. μ = 2.5, s = 20, speed 0.150, final axis extension 1.6x