Table 1. Allelic replacement at the treA locus using circular or linearized recombinant cosmids.
| Plasmid/cosmid | Experimenta | Homology to treA locusb | treA–/totalc |
|---|---|---|---|
| Circular | |||
| pTRE12 | 1 | 2.3/1.2 | 0/25 |
| pTRE18 | 1 | 2.3/1.2 | 0/25 |
| cTRE19 | 1 | ND | 2/24 |
| cTRE20 | 1 | ND | 5/24 |
| cTRE20 | 2 | ND | 8/24 |
| cTRE20 | 3 | ND | 0/24 |
| Linearized | |||
| pTRE12/NotI | Ref. 10 | 2.3/0.7 | 4/75 |
| cTRE20/ClaI | 2 | ND | 13/25 |
| cTRE20/SfiI | 2 | ND | 2/3 |
| cTRE20/DNase I (1 min) | 3 | ND | 1/25 |
| cTRE20/DNase I (2 min) | 3 | ND | 3/25 |
| cTRE20/DNase I (5 min) | 3 | ND | 6/25 |
| cTRE20/DNase I (10 min) | 3 | ND | 2/20 |
| cTRE20/DNase I (15 min) | 3 | ND | 8/24 |
aThree independent experiments were performed.
bLength in kb of the DNA homologous with the treA locus located on each side of the selectable marker in pTRE12 and pTRE18. These values are not known but >5 kb for cTRE19 and cTRE20. ND, not determined.
cNumber of transformants with a treA– phenotype relative to the total number of transformants tested. The treA phenotype was scored on minimal trehalose medium.