When transforming bacteria with a plasmid, we are often interested in how many plasmids have (on average) ended up in each bacterial cell (i.e. the copy number).

We can use quantitative PCR to do this, where we are interested in the cycle number when the amplified product crosses a predetermined threshold (Cq) as shown below:

This will enable us to compare the threshold (Cq) values for genes on the plasmid with genes on the bacterial chromosome.

In this scenario, you have transformed E. coli with the plasmid pCOOKIE.  The plasmid carries the Amp gene, while the E. coli contains the SAM gene on its chromosomal DNA.  You have primers for both the Amp and the SAM genes and you use these to perform quantitative PCR on your transformed cells.

You amplify the Amp and the SAM genes in triplicate using quantitative PCR and get the following results:

The equation for calculating copy number of a plasmid is:

Using the data provided, what is the copy number for pCOOKIE in your experiment?

* Round your answer to the nearest whole number; figures only; no units.