NEETZoologyBiotechnology - Principles and Processes
A researcher wants to clone a foreign gene into a plasmid vector. The vector has three recognition sites for restriction enzyme X and a single recognition site for restriction enzyme Y. The recognition site for enzyme Y is located within the tetracycline resistance gene ( tet^ R ). Which enzyme should the researcher choose for the cloning experiment, and what will be the immediate consequence of successful insertion?
Options
- AEnzyme X, because multiple recognition sites increase the probability of successful ligation.
- BEnzyme Y, resulting in the insertional inactivation of the tetracycline resistance gene.
- CEnzyme X, resulting in the insertional inactivation of the origin of replication.
- DEnzyme Y, resulting in the generation of several vector fragments.
Correct answer
B. Enzyme Y, resulting in the insertional inactivation of the tetracycline resistance gene.
Step-by-step solution
In order to link the alien DNA, a cloning vector needs to have very few, preferably single, recognition sites for the commonly used restriction enzymes. Presence of more than one recognition site within the vector (as with enzyme X) will generate several fragments, which will complicate the gene cloning process. Therefore, the researcher must avoid enzyme X and choose enzyme Y, which has a single recognition site. Since the recognition site for enzyme Y is located within the tetracycline resistance gene, the insert