How do we ensure that only E coli that contain the gene for

How do we ensure that only E. coli that contain the gene for Taq DNA polymerase will grow?

Solution

Taq DNA polymerase is an enzyme used in almost all research labs. This enzyme is originally found in bacteria Thermus aquaticus. For the commercial purpose and to obtain more yield, this is gene is cloned in E.coli bacteria.

General explanation: Whenever a gene is clones in a particular organism/ bacteria. The required gene is first inserted in a plasmid (expression vector) and this plasmid is allowed to transfer inside the bacterial cell (transformation). Then transformed cell undergo selection to allow only transformed cells to grow and exclude non-transformed cell. For this we have selection markers in plasmid (example: antibiotic resistance gene). Only the cell with plasmid will grow in respective antibiotic media. Finally the selected cells are allowed to grow at high scale to get required product.

Therefore use proper selective marker (antibiotic) as per the plasmid used to get only Taq polymerase cloned E. coli to grow.