Table 4.

Effect of mutations on the frequency of tract alteration in the (AC)₅₁ insert in the absence of SOS induction

Relevant genotype	Tract alteration frequency*
lexA (Ind−)	2.1  ×  10−4  (1.0)
mutS lexA (Ind−)	5.1  ×  10−3  (24)
polA1 lexA (Ind−)	2.8  ×  10−4  (1.3)
ΔpolA (F′ Klenow) lexA (Ind−)	9.9  ×  10−4  (4.7)
uvrD lexA (Ind−)	3.2  ×  10−4  (1.5)

^*Tract alteration frequencies represent the average of at least three independent determinations. Numbers in parentheses represent the rates of tract length alteration (fold) relative to the rate in the lexA (Ind⁻) strain.