Table 1.

Statistics of SSOGs and their various subsets for the nine most represented taxonomic classes

Taxonomic class	No. of species	No. of SSOGs	Pct. of SSOGs out of species pangenome (average)	No. of SSOGs with d_N/d_S < 0.5	No. of SSOGs >800 nt	Pct. of SSOGs that are cloud (average)	No. of SSOGs with viral hits	No. of SSOGs matching alt. frames of conserved genes	No. of de novo candidates
Actinobacteria	124	18,932	4.06	535	472	85	268	261	40
Alphaproteobacteria	61	13,398	5.38	569	721	79.6	174	252	15
Bacilli	488	40,630	2.20	2,311	1295	81.3	3598	400	56
Bacteroidia	603	189,793	4.41	5576	2954	87.8	4074	3068	389
Clostridia	1868	218,177	2.38	9760	10,098	86	9667	2390	317
Coriobacteriia	704	21,808	0.72	976	673	91.4	517	204	41
Gammaproteobacteria	288	45,025	2.51	1497	1340	89.7	1151	743	127
Negativicutes	148	18,916	2.12	922	437	90.6	1716	317	11
Vampirovibrionia	63	5794	2.34	363	178	77.2	542	66	11
All	4644	631,104	2.6	25,355	21,493	86.8	23,147	8477	1075

Large-scale investigation of species-specific orphan genes in the human gut microbiome elucidates their evolutionary origins