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Question
A plasmid without a selectable marker was chosen as vector for cloning a gene. How does this affect the experiment?
Solution
In a gene, cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector (the step would not be affected) and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant/plasmid DNA, in the absence of a selectable marker, it will be difficult to distinguish between transformants and non-transformants, because role of the selectable marker is in the selection of transformants.
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