Fig. 4
Motion analysis for strains with different genomic separations. a When the relative orientation of two particles is maintained as they proceed along their trajectories (indicated as lines) their motion is considered isotropic (bottom), when orientation changes over time motion is anisotropic (top). A statistic D was calculated as a measure of anisotropy (Materials and Methods; Fig. 4). Larger D values correspond to greater anisotropy. D is observed to generally increase with genomic separation (b). In c the mean D is plotted against the mean distance (R 2 = 0.43). d To assess the correlation of the direction of motion of the two operators flanking a locus, comparisons of the vectors describing the motion of each operator were made at each time point. An RV coefficient was calculated for this purpose. The general trend observed was a decrease of motion correlation as the genomic separation between the operators increased. However, for the 64 kb and 42 kb strains which adopt a more compact configuration, the trend was not observed