TABLE 1.

Summary of 16S rRNA-based clonal analyses of diversity of uncultivated bacteria^a

Habitat type	No. of studies	Bacterial divisionb
		No. of sequencesc	Proteobacteriad
			αc	β	γ	δd	ɛe	Cytophagales	Actinobacteria	Low-G+C gram positivese	Acidobacterium	Verrucomicrobia	Spirochetes	Nitrospira	GNS	OP11	Planctomycetes	Green sulfur	TM7	TM6	Thermus/Deinococcus	Cyanobacteriac	Synergistes	OP8	Termite group I	OS-K	Chlamydia	OP3	OP10	WS1	OP5	Marine group A	Fibrobacter	Flexistipes	Dictyoglomus	Thermotogales	Thermodesulfobacterium	Aquificales
Geothermal	10	212	○	○		○		○			○		○	○	○		○	○			○					○										○		○
Soil	16	743	•	○	○	○		○	•	○	•	•			○		○
Marine	23	687	•	○	•	○		○	○	○		○					○					○
Freshwater	4	107	•	○					○		○
Wastewater	5	430	•	•	•	○		○	•	○		○			○		○
Pollutant associated	7	202	○	○	○	○	○	○	○	○	○
Acid metal leaching	2	21	•	○	•			○	○	○	○			•
Subsurface	6	229	○	•	•	○	○		○	•				○	○	○												○
Symbionts and commensals	10	280			•			○		○			○
Disease associated	3	7		○	○			○		○			○
Totals	86	2,918

^aAn expanded version of this table detailing individual studies is available at http://crab2.berkeley.edu/∼pacelab/176.htm. 

^bIncidence of division-level representatives in studies of particular habitat types ranked from most represented to least represented divisions: >75% (•), 25 to 75% (○), or <25% (no symbol) of studies have representatives of division. 

^cExcluding organelles. 

^dProteobacteria are presented at the subdivision level due to the extensive sequence representation of this division. 

^eCannot establish as a monophyletic group in all analyses.