Table 3.

Location and conservation characteristics of homoplasmic tRNA variants and pathogenic tRNA mutations.

Location	Changea	Positional conservationb	Homoplasmic variants		Pathogenic mutationsc
			Total # (%)	# conserved pairingd	Total # (%)	# conserved pairingd
Loop		<100%	37 (47)		11 (12)
		100%	4 (5)		18 (20)
Stem	MM>WC	<100%	13 (17)	2	0 (0)
	MM>WC	100%	1 (1)	1	2 (2)	1
	MM>MM	<100%	3 (4)		0 (0)
	MM>MM	100%	1 (1)		0 (0)
	WC>mMM	<100%	16 (21)	1	31 (34)	13
	WC>mMM	100%	3 (4)	3	25 (28)	20
	WC>sMM	<100%	0 (0)		0 (0)
	WC>sMM	100%	0 (0)		3 (3)
Total			78	7	90	34

Underlined data represent types of variants only present in the homoplasmic variants or pathogenic mutations group.

MM>MM = mismatch base pair to another mismatch base pair.

WC>mMM =WC to a mild mismatch base pair, mild mismatch base pairs are A·C, C·A, G·U and U·G.

WC>sMM = WC to a severe mismatch base pair, severe mismatch base pairs are all mismatch base pairs excluding A·C, C·A, G·U and U·G.

^aMMNWC = mismatch base pair to Watson–Crick base pair (WC).

^bAs determined in 31 mammalian mitochondrial genomes (Helm et al., 2000).

^cSee Supplementary Table 3 for detailed list.

^dConserved pairing: 100% conserved WC or N90% G·U and U·G as determined in 31 mammalian mitochondrial genomes (Helm et al., 2000).