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Inserting the gene into a Vector


A Vector = the term used for an agent that can carry something from one organism to another.

One type of Vector often used to transfer genes is a Plasmid.

Plasmids are small circular pieces of DNA found in most bacteria. They are completely separate from the main bacterial DNA and lie freely in the cytoplasm. They are not however useless and many contain genes which make bacteria resistant to a particular antibiotic.

Scientists often use this antibiotic resistance to ensure that their required gene has been inserted into a plasmid to make the new recombinant DNA molecule. Using them as Genetic markers.

This is carried out as follows: -


The recombinant plasmid will no longer be able to express Ampicillin resistance .

However, not all the plasmids will take up the Donor DNA and some will just re-glue themselves back together.


How do we identify which plasmids contain the gene we require and which have not?

To do this we have to put the plasmids into another Vector, that is put them back into bacterial cells to make more copies or clones.