TABLE 2.

Distribution of cbbL OTUs within the clone libraries

Area	OTU	Accession no.	% Nucleotide sequence divergencea	No. of clones				Frequency of OTU (%)b
				cbbL clone libraries
				Hydrothermal vent water	Sediment	Chimney	Symbiont
TAG Mound	TAG-Chm(I)-1	AB038680	4.6			45		90
	TAG-Chm(I)-2	AB038681	0			2		4
	TAG-Chm(I)-3	AB038682	0			1		2
	TAG-Chm(I)-4	AB038683	0			1		2
	TAG-Chm(I)-5	AB038684	0			1		2
Total						50
Mid-Okinawa Trough	MOT-Hvw(I)-1	AB038636	2.2	5				10
	MOT-Hvw(I)-2	AB038638	3.8	6				12
	MOT-Hvw(I)-3	AB038639	3.2	6				12
	MOT-Hvw(I)-4	AB038644	0	3				6
	MOT-Hvw(I)-5	AB038645	0	3				6
	MOT-Hvw(I)-6	AB038646	0	3				6
	MOT-Hvw(I)-7	AB038641	7.2	5				10
	MOT-Hvw(I)-8	AB038640	2.8	3				6
	MOT-Hvw(I)-9	AB038637	0	2				4
	MOT-Hvw(I)-10	AB038642	0	2				4
	MOT-Hvw(I)-11	AB038643	0	2				4
	MOT-Hvw(I)-12	AB038635	3.2	10				20
	MOT-Sym(I)-1	AB038634	4.4				50	100
Total				50			50
Sagami Trough	ST-Sed(I)-1	AB038675	3.8		35			70
	ST-Sed(I)-2	AB038676	0		5			10
	ST-Sed(I)-3	AB038679	0		1			2
	ST-Sed(I)-4	AB038677	1.6		6			12
	ST-Sed(I)-5	AB038678	1.4		3			6
Total					50
Japan Trench	JT-Sed(I)-1	AB038633	3		38			76
	JT-Sed(I)-2	AB038632	0.8		12			24
Total					50
Northern Okushiri Ridge	NOR-Sed(I)-1	AB038687	4.6		20			40
	NOR-Sed(I)-2	AB038685	8		19			38
	NOR-Sed(I)-3	AB038688	5		10			20
	NOR-Sed(I)-4	AB038686	0		1			2
Total					50

^a% Nucleotide sequence divergence is the percentage of mismatched nucleotides between the clones within the OTU compared with the total length of analyzed nucleotide sequences (500 bp) (19). However, the clones within each OTU showed 100% amino acid identity. 

^bFrequency of the OTU compared with the total number of clones analyzed in the clone library.