Helitron (biology)

A helitron is a transposon found in eukaryotes that is thought to replicate by a so-called "rolling-circle" mechanism. This category of transposons was discovered by Vladimir Kapitonov and Jerzy Jurka in 2001. The rolling-circle process begins with a break being made at the terminus of a single strand of the helitron DNA. Transposase then sits at this break and at another break where the helitron targets as a migration site. The strand is then displaced from its original location at the site of the break and attached to the target break, forming a circlular heteroduplex. This heteroduplex is then resolved into a flat piece of DNA via replication. During the rolling-circle process, DNA can be replicated beyond the initial helitron sequence, resulting in the flanking regions of DNA being "captured" by the helitron as it moves to a new location.