<p>(A) Computationally reconstructed trajectories (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064506#pone.0064506.s010" target="_blank">Movie S6</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064506#pone.0064506.s011" target="_blank">S7</a>). White mark at the end of trajectory indicates the latest point. Red, blue, and green arrows at the lower left indicate the anterior–posterior axis, right–left axis, and proximal–distal axis, respectively. (B) Histograms of one-step velocity (top row) and the ratio of actual migration path length to linear displacement over 30 min (bottom row). Nuclear positions at the first time-point were classified into two areas according to two sets of criteria, lateral (cyan) or distal (magenta) and forward (orange) or rear (green). (C) Comparison of triangles connected neighboring nuclei at first time point and after 3 hours (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064506#pone.0064506.s012" target="_blank">Movie S8</a>). Nuclear positions at the first time-point were classified into two areas, lateral (cyan) or distal (magenta). After 3 hours, the areas of the triangles become larger and some triangles overlap each other, indicating that nuclei in the mesoderm do not migrate in straight lines.</p
