Fig 3. Incidence of genes underlying PGN metabolism and related pathways from 17 aphid host-symbiont species.

Filled cells indicate gene presence, while empty cells indicate gene absence. For aphid genes, numbers indicate the number of gene paralogs identified per genome. For symbiont genes, filled cells all indicate a single copy per genome. All symbionts are Buchnera except those of Geopemphigus sp, indicated by an asterisk, which contains a novel Bacteroidetes symbiont. Host species containing known co-obligate or uncharacterized facultative symbionts are indicated with an obelisk (†) or a double obelisk (‡), respectively. Each species code represents the combined first two letters of the genus and species (S1 Table). Colored circles indicate genes with dual-membership in the pathway of the same color, while black indicates dual-membership in amino acid metabolism.