Figure 1.

Schematic representation of recursive segmentation and moving-window methods for island detection. (A) The recursive segmentation technique. The dashed line shows the value of MJSD, D^m, across each possible split location. If D_max^m is statistically significant, the sequence is segmented at that point, represented by a vertical bar. In this example, four splits are made resulting in five segments; values of D_max^m that are not significant are denoted as ns. Comparison of segments to the genome as a whole shows two segments are islands and three represent the core genome. (B) The moving-window technique. Values are calculated for windows of a specified size; windows with values over a predetermined threshold are identified as atypical and annotated as an island (gray region). Here, there is insufficient signal for the 5′ region to be marked as a putative island, resulting in a false negative.