cmlc2-GFP cells in left-anterior (LA), left-posterior (LP), right-anterior (RA), and right-posterior (RP) quadrants were tracked and different parameters were measured using Imaris Software. Speed variation indicates speed of a cell during a given time interval. Total speed, displacement rate, and meandering index were determined as described in Experimental Procedures and Supplemental Figure 1. Note the higher speed (A, C and E), displacement rate (G) and meandering index (I) of posterior cells as compared to anterior cells in wild type. These differences are reduced in LZoep mutants. Cardiomyocytes in LZoep mutants have lower speed (B, D and F), displacement rate (H) and meandering index (J) as compared to wild type. Differences between posterior and anterior cells are attenuated in LZoep mutants. Vectors of individual cells illustrate the angle and length of x/y displacement of cells (A: anterior; P: posterior; L: left; R: right). Note the leftwards and anterior displacement of wild type cells (K). LZoep mutant cells displace less and mostly anteriorly (L). Statistics: E) p<0.05 ; F) p>0.05; G) LA vs LP, p<0.05; RA vs RP, p<0.05; LA vs RA, p>0.05; LP vs RP, p>0.05; H) LA vs LP, p<0.05; RA vs RP, p<0.05; LA vs RA, p>0.05; LP vs RP, p>0.05; I) LA vs LP, p<0.05; RA vs RP, p<0.05; LA vs RA, p>0.05; LP vs RP, p>0.05; J) LA vs LP, p<0.05; RA vs RP, p<0.05; LA vs RA, p>0.05; LP vs RP, p>0.05.