Table 2.

Mutational Profiles of NNN, DB[a,l]P, and Their Combination in lacI Mouse Tongue^a

	percentage of mutations
class	NNN	DB[a,l]P	NNN + DB[a,l]P obs.	NNN + DB[a,l]P exp.
G:A	18	16.7	42.0b	17.4
G:T	16	33.3	14.0	23.9
G:C	10	7.1	16.0	8.7
A:G	10	7.1	2.0	8.7
A:C	4	9.5	4.0	6.5
A:T	30	14.3	12.0	22.8
indel	12	11.9	10.0	12.0
	100	100	100	100

^aTo test whether there were any statistically significant differences between the observed and expected percentages for each mutation class, an “N − 1” chi-squared test was employed.

^bp < 0.05 for the difference between the observed and expected percentages.