This enzyme serves several important functions. 

• It plays a crucial role in DNA replication, DNA recombination, and DNA repair, helping to join the nicks and form a phosphodiester bond between the nucleotides. This helps to maintain genomic integrity. 
• Researchers use DNA ligase with restriction endonuclease enzyme in order to insert DNA segments, often genes, into the plasmid. 
• DNA ligases that are purified from various organisms are used in gene cloning to join DNA molecules together with the aim of generating recombinant DNA. 
• E. coli DNA ligases are particularly useful for high-efficiency cloning of full-length cDNA.