A plasmid has accepted the gene of interest, such as gene coding for streptomycin. How can we make clones of this plasmid?

Options

A. Inserting it into a virus to generate multiple copies
B. Treating it with a restriction enzyme in order to cut the molecule into small pieces
C. Inserting it into a suitable bacterium in order to produce multiple copies
D. Running it on a gel electrophoresis in order to determine the size of the gene of interest

Answer

To make clones of a plasmid that has accepted a gene of interest, such as the gene coding for streptomycin, we can follow these steps:

### Step-by-Step Solution:

1. **Selection of the Plasmid**: Start with a plasmid that has been engineered to include the gene of interest (in this case, the gene coding for streptomycin). Ensure that the plasmid has a suitable origin of replication and selectable markers.

**Hint**: Choose a plasmid that has features for replication and selection.

2. **Transformation into Bacteria**: Introduce the recombinant plasmid into a suitable bacterial host (commonly E. coli) through a process called transformation. This can be done using methods like heat shock or electroporation.

**Hint**: Use methods that facilitate the uptake of plasmid DNA by bacterial cells.

3. **Selection of Transformed Bacteria**: After transformation, plate the bacteria on agar medium containing an antibiotic (like streptomycin) that corresponds to the selectable marker in the plasmid. Only the bacteria that have successfully taken up the plasmid will survive and grow.

**Hint**: Use selective media to isolate only those bacteria that contain the plasmid.

4. **Colony Growth and Cloning**: Allow the bacteria to grow and form colonies. Each colony originates from a single bacterium that has taken up the plasmid, thus each colony contains clones of the plasmid.

**Hint**: Observe the growth of colonies to ensure successful cloning.

5. **Plasmid Isolation**: Harvest the bacteria and isolate the plasmid DNA from the bacterial cells. This can be done using a plasmid extraction kit or a standard alkaline lysis method.

**Hint**: Use a reliable method for plasmid purification to ensure high yield and quality.

6. **Verification of Clones**: Use techniques such as restriction enzyme digestion or PCR followed by gel electrophoresis to verify that the plasmid contains the gene of interest.

**Hint**: Confirm the presence of the gene through molecular biology techniques.

### Summary:
To clone a plasmid with a gene of interest, you need to transform it into a suitable bacterium, select for those that have taken up the plasmid, allow them to grow, isolate the plasmid, and verify its presence.