Table 2.

Dual complementarity of second bases in separate organisms and consensus tRNAs representing main kingdoms

Organism or group	No. of pairs of tRNAs with complementary anticodons	No. of pairs with complementary second bases in the acceptors	No. of pairs with noncomplementary second bases in the acceptors
E. coli (Eubacteria)	32	24	8**
H. volcanii (Archaebacteria)	29	24	6**
S. cerevisiae (Yeast)	24	20	4**
Chloroplasts	26	19	7**
Cytoplasm of plants	20	16	4**
Cytoplasm of animals	27	18	9**
Mitochondria of single cell or fungi	18	12	6*
Mitochondria of plants	17	12	5*
Mitochondria of animal	17	9	8*
Pooled data	210	154	56**
Common consensus (from ref. 6)	32	29	3**

All tRNAs sequence data are retrieved from ref. 7. The table shows that almost ideal dual complementarity represented by common consensus tRNAs diverged in different phyletic pathways. Therefore, consensus tRNAs show a highest index of the dual complementarity. Yet, all groups tested, except for mitochondrial tRNAs, still show significantly nonrandom dual complementarity. Nonrandomness of the dual complementarity was statistically tested using normal approximation to binomial distribution (without continuity correction) and assuming two-tail P values. 

^**Extremely nonrandom (P = 0.0004–0.008). **Significantly nonrandom (P = 0.016–0.04). *Insignificantly nonrandom (P ≥ 0.16).