Which among the following enzyme joins the ends of two strands of nucleic acid in recombinant DNA technology ?

Ligase

In recombinant DNA technology, the enzyme that joins or ligates the ends of two strands of nucleic acid (such as DNA) together is called "Ligase."

Ligase plays a crucial role in the formation of recombinant DNA molecules. It catalyzes the joining of DNA fragments by creating phosphodiester bonds between the sugar-phosphate backbones of the DNA strands. This process is essential when creating recombinant DNA molecules during genetic engineering experiments, such as inserting a specific gene into a vector (like a plasmid or a viral genome) to produce a recombinant DNA molecule.

The linking of foreign DNA with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. When cut by the same restriction enzyme, the resultant DNA fragments have the same kind of ‘sticky-ends’ and, these can be joined together (end-to-end) using DNA ligase.