Okazaki fragment

The Okazaki fragments, named after their discoverers, are fragments of a discontinuous strand of DNA produced during the chromosomal replication of DNA.

Formation of Okazaki fragments

DNA replication occurs in a pre-determined direction which occurs in the reverse direction in the two strands. In one of the new strands, the replication fork therefore advances in the opposite direction to replication. As a result, replication must be carried out in several stages, each leading to a small fragment of DNA produced: the Okazaki fragment.

As this so-called discontinuous strand is synthesised the DNA primers at the start of the Okazaki fragments are hydrolysed and a DNA ligase enzyme binds the fragments end to end.