Table 3.

Frequency of major classes of mutations generated during in vitro gap-filling replication by pol III holoenzyme and by pol V

Mutation	Mutation frequency × 10−5 per cro gene		Mutation frequency × 10−5 per nucleotide		Pol V/Pol III
	Pol III	Pol V	Pol III	Pol V
Base substitution	33.1	1,657	0.38	19.0	50
Transition	17.9 (30%)	529 (25%)	0.21	6.1	30
Transversion	15.2 (25%)	1,128 (53%)	0.17	13.0	74
Frameshift	27.6 (45%)	460 (22%)	0.14	2.3	17
Total point mutations	60.7	2,118	0.52	21.3	35/41*

Mutation frequency per cro gene was calculated based on the data presented in Tables 1 and 2. Mutation frequency per nucleotide was calculated by dividing the mutation frequency per gene by the number of mutable sites (87 for base substitution and 201 for frameshift), as described in Materials and Methods. 

^*The ratio is 35 for mutation frequency per gene and 41 for mutation frequency per nucleotide. The difference stems from the fact that the number of mutable sites is different for base substitutions and frameshifts.