Proportions of native and HGT genes that formed new operons or were imported as operons
History of the gene | |||||
|---|---|---|---|---|---|
| Native | |||||
| Ubiquitous | Typical | HGT | |||
| Formed a new operon | 20% (39/200) | 22% (474/2164) | 17% (58/345) | ||
| At time of HGT | — | — | 9% (31/345) | ||
| Since Salmonella | 2% (3/200) | 8% (174/2164) | 9% (13/138) | ||
| In an imported operon | 2% (3/200) | 14% (294/2164) | 48% (165/345) | ||
[i] For the analysis of newer operons (since Salmonella), we included only HGT genes with older ages, so that all genes were in the E. coli lineage for the entire time period analyzed and had equal opportunity to form new operons. The three single-copy ubiquitous genes that are in imported operons reflect rare errors of our automated classification and not HGT of these genes (see Methods).