Table 2. Summary of DnaE and PolC polymerases (⩾100 amino acids) in six metagenomic samples.

Samples	DnaE1+DnaE3	DnaE2	PolC	unclassified	Total	DnaE2%
North Pacific Ocean	1414	307	209	543	2473	21.71
Sargasso sea	1353	283	798	110	2544	20.92
Fresh watera	872	96	85	388	1441	11.01
Peru Margin sedimentb	92	52	29	19	192	56.52
Minnesota Farm	66	45	5	40	156	68.18
FACEc	4406	2450	393	2034	9283	55.61

The number of polymerases is listed in each group for each sample.

^aTwelve samples from fresh water are all recruited for further data saturation analysis in Figure 2.

^bSix samples of marine sediment of different depths are further compared in order to clarify the association between DnaE2% and GC content variations in Supplementary Table S2.

^cTwenty samples from FACE (Free-Air Carbon Dioxide Enrichment) sites are also recruited for further data saturation analysis in Figure 2.