TABLE 1.

Ribozyme activities and deletions for isolates from round 5, 6, and 7 of the selection from the deletion/substitution pool

			Number of deleted nucleotides
Ribozyme	Activity (min−1)	Length (nt)	R1	R2	R3	R4	R5	Total
Init. pool	n/a	163	(15)	(25)	(8)	(10 + 11)	(7)	(76)
da.5.03	0.04	119	3	9	4	27	1	44
da.5.11	0.06	124	3	6	4	24	2	39
da.6.05	0.07	120	4	9	4	26	0	43
da.6.06	0.06	131	10	12	2	6	2	32
da.6.13	0.05	137	2	22	0	2	0	26
da.6.17	0.04	136	4	14	4	5	0	27
da.7.02	0.08–0.13	124	4	7	3	25	0	39
da.7.08	0.05–0.09	131	9	10	4	8	1	32
da.7.13	0.07–0.10	123	2	12	4	21	1	40
da.7.18	0.05–0.06	127	10	11	4	10	1	36

In parentheses are the numbers of deletion/substitution couplings used to create a given variable region (Fig. 2C ▶). Bold numbers highlight deletions significantly larger than expected by chance (assuming a deletion frequency of 0.25, P < 0.01).