TABLE 1

Frequencies of intrachromosomal recombination between mismatched sequences

DNA substrateaCell lineCopy no.bNo. of cells tested (×10–6)cNo. of HATR coloniesRecombination frequency (×108)d
pAA-CC112265223
22250 (500)5310
32270 (540)7313
Mean = 14 ± 2.1
pAG-CT112800<0.4
2128010.4
3260 (520)91.7
Mean = 0.9 ± 0.6
pAA-TC11342102.9
213494210.0
Mean = 7.5 ± 2.1
Corrected = 5.5
pAG-TT11337257.4
11522346.5
21441286.3
Mean = 6.7 ± 1.4
Corrected = 5.7
pAG-TG11358102.8
2135641.1
Mean = 2.0 ± 1.0
pAG-CG113560
214300
314300
Mean < 0.08
pAG-AG1128841.4
2134982.3
Mean = 1.9 ± 1.1
Corrected = 1.6
pAG-AT1133751.5
2135451.4
Mean = 1.5 ± 0.9
Corrected = 1.2
  • a Substrates are as described in materials and methods and depicted schematically in Figure 1. Raw data for cell lines containing pAA-CC and pAG-CT were previously reported (Waldman and Liskay 1988).

  • b Number of copies of relevant DNA substrate in the particular cell line.

  • c The total number of copies of integrated substrate plated is given in parentheses.

  • d Number of HATR colonies divided by total number of copies of integrated DNA substrate plated for each cell line. The mean recombination frequencey is the total number of HATR colonies divided by total number of copies of integrated substrate plated for all cell lines containing a particular DNA substrate combined; 95% confidence limits are shown. The corrected reconbination frequency is the mean recombination frequency multiplied by the fraction of analyzed HATR colonies that had actually undergone a gene conversion (see Table 2). Corrected frequencies are presented only for substrates from which one or more nonrecombinant HATR segregants were recovered.