Selection Efficiency of the Filter Vector
| Number of colonies | Ratio chloramphenicol/ampicillin | ||
| Chloramphenicol (24 μg/mL) | Ampicillin (12 μg/mL) | ||
| 32,000 | 400 | 80:1 | |
[i] The number of clones before (chloramphenicol) and after ampicillin preselection is given.