Table 1.

Recombination and mutation rates

Recombination rates (× 10−7)*
	Cell lines
Cells	GS21-15, ERCC1+	GS21-13, ERCC1−
TK−	15 ± 3     (11)	48 ± 23  (29)
TK− APRT−	1.4 ± 0.5  (1.4)	6 ± 3    (3.4)
APRT−	14 ± 3     (11)	31 ± 25  (19)
Mutation rates (× 10−7)†
	Cell lines
Cells	GS782, ERCC1+	GS96, ERCC1−
APRT−	1.8 ± 0	13 ± 8

^*These rates represent the average ± SD of three fluctuation tests. Rates adjusted to reflect only homologous recombination events (by subtracting out the proportion of events caused by point mutations and rearrangements) are indicated in parenthesis. Because the recombination rates from the ERCC1⁺ cell line GS21-15, which contains the identical APRT gene structure as GS21-13, are the same as previously reported results (22), we have included the previously reported rates in these data. 

^†These rates represent the average ± SD of two fluctuation tests for GS7B2 and three fluctuation tests for GS96.