Table 2. Numbers of lateral genes with single or multiple donors in each genome within the ECS dataset.

Group	Organism	Number of genes	Number of lateral genes	Donor groups	Number of lateral genes with 1 donor	Number of lateral genes with 2 donors	Number of lateral genes with ≥3 donors
D	E. coli SMS 3 5	4744	0	–	–	–	–
D	E. coli IAI39	4725	1469	S	1469	–	–
D	E. coli UMN026	4878	2930	S, B1, B2	1004	769	1157
S	Shigella flexneri 5 8401	4336	1030	E, A, B1	855	120	55
S	Shigella flexneri 2a	4053	1142	D, E, A	650	288	204
S	Shigella flexneri 2a 2457T	4385	1188	E, A, B1	880	158	150
S	Shigella sonnei Ss046	4563	1842	D, E, A, B1	638	626	578
S	Shigella boydii Sb227	4391	1859	D, E, A, B1	974	538	347
S	Shigella boydii CDC 3083 94	4532	1280	A, B1	1093	187	–
S	Shigella dysenteriae	4063	1300	A	1300	–	–
E	E. coli O157 : H7	5204	3685	B1	3685	–	–
E	E. coli O157 : H7 EDL933	5286	3492	B1	3492	–	–
A	E. coli K12 substr W3110	4213	1211	S, E, B1	1050	117	44
A	E. coli K12 substr MG1655	4140	2045	D, E, B1, B2	927	465	653
A	E. coli HS	4366	2585	D, S, E, B1, B2	891	667	1027
A	E. coli C ATCC 8739	4434	0	–	–	–	–
B1	E. coli E24377A	4729	2945	S, E, A, B2	1469	1068	412
B1	E. coli 55989	4953	3108	S, E, A, B2	1526	1081	501
B1	E. coli SE11	4684	2918	S, E, A, B2	1448	1049	421
B1	E. coli IAI1	4385	3157	D, S, E,A, B2	1161	991	1005
B2	E. coli 0127 H6 E2348 69	4809	1561	E, B1	1120	448	–
B2	E. coli 536	4542	1183	E, B1	855	328	–
B2	E. coli CFT073	4897	0	–	–	–	–
B2	E. coli ED1a	5012	1230	S, E	941	305	–
B2	E. coli UTI89	4827	563	B1	563	–	–
B2	E. coli S88	4688	1088	E, B1	801	287	–
B2	E. coli APECO1	4878	592	B1	592	–	–

The genomes are grouped into six groups following a phyletic criterion (see text).