What function do ligases perform in molecular biology?

Ligases play a crucial role in molecular biology by joining DNA fragments together. This is achieved through the formation of covalent bonds between the ends of these fragments, effectively sealing nicks in the DNA backbone. This function is especially important during DNA replication and repair processes, where the continuous strands of DNA must be linked together to create a complete, functional molecule.

In the context of genetic engineering and biotechnology, ligases are often used in cloning procedures to insert DNA fragments into plasmids or to join together pieces of DNA generated by restriction enzyme digestion. This allows for the assembly of larger constructs needed for a variety of applications, such as gene expression studies or the production of recombinant proteins. The ability to form stable bonds between DNA fragments is fundamental for maintaining the integrity of genetic information and enabling its manipulation for research and therapeutic purposes.