Figure 3.

Inferred LGT events between 135 distinct bacterial genera. (a) An LGT heatmap. The colored side bars indicate class using the color mapping of Figure 2. The row and column genus order is the same. The number of transfers is shown in a white-yellow-red color scale with darker colors indicating a higher proportion of transfer events. Color intensity is relative to the largest number of transfers in a row. Relationships with fewer than 5% of the maximum transfer events for a row or only a single transfer event were filtered out. (b) Each node of the LGT affinity graph represents a bacterial genus, colored by class and scaled relative to the number of genomes representing that genus (1–15). Two genera are connected by an edge if the number of inferred LGT events between them exceeds 5% of the number of homologous genes common to both genomes. The shade of an edge is proportional to this ratio of LGT events to common genome size; black edges indicate relationships with at least as many LGT events as the size of their common genome. The thickness of an edge scales relative to the actual number of inferred transfers (between 2 and 370) with thicker edges indicating more transfers. The graph is shown with a spring-loaded layout.