What is the role of ligase in genetic engineering?

The role of ligase in genetic engineering is to "paste" DNA fragments together. This enzyme facilitates the formation of phosphodiester bonds between the 3' hydroxyl end of one DNA fragment and the 5' phosphate end of another, effectively joining them into a continuous strand of DNA. This is especially important during the cloning process, where ligase is used to combine the insert (the DNA fragment of interest) with a vector (the DNA molecule used to deliver the insert into a cell).

In the context of genetic engineering, ligase enables the successful construction of recombinant DNA molecules, which can then be introduced into host cells for further study, protein production, or other applications. The ability to join DNA fragments reliably is a foundational technique in biotechnology, making ligase an essential enzyme in the manipulation and study of genetic material.