How do I know if my plasmid is a high- or low copy number type?
FAQ ID -350
Find out which origin of replication your plasmid contains, and look at the table below for classification into high-copy or low-copy types. This table can also be found online at the QIAGEN Plasmid Resource Center in the section 'Growth of bacterial cultures; Plasmid Copy Number' . A way to determine experimentally if the copy number of your plasmid is high or low is to perform a miniprep. A high-copy plasmid should yield between 3-5 ug DNA per 1 ml LB culture, while a low-copy plasmid will yield between 0.2-1 ug DNA per ml of LB culture.
Origins of replication and copy numbers of various plasmids and cosmids
| DNA construct |
Origin of Replication |
Copy number |
Classification |
| Plasmids |
|
|
|
| pUC vectors |
pMB1* |
500–700 |
high copy |
| pBluescript® vectors |
ColE1 |
300–500 |
high copy |
| pGEM® vectors |
pMB1* |
300–400 |
high copy |
| pTZ vectors |
pMB1* |
>1000 |
high copy |
| pBR322 and derivatives |
pMB1* |
15–20 |
low copy |
| pACYC and derivatives |
p15A |
10–12 |
low copy |
| pSC101 and derivatives |
pSC101 |
~5 |
very low copy |
| Cosmids |
|
|
|
| SuperCos |
pMB1* |
10-20 |
low copy |
| pWE15 |
ColE1 |
10-20 |
low copy |
* The pMB1 origin of replication is closely related to that of ColE1 and falls in the same incompatibility group. The high-copy plasmids listed here contain mutated versions of this origin.