DNA ligase is an enzyme that repairs irregularities or breaks in the backbone of double-stranded DNA molecules. It has important role in the process of DNA replication and DNA repair. It has three general functions: It seals repairs in the DNA, it seals recombination fragments, and it connects Okazaki fragments (small DNA fragments formed during the replication of double-stranded DNA). DNA ligase functions by forming a bond between the end of a “donor” nucleotide and the end of an “acceptor” nucleotide.