A DNA segment that transposes as a rolling-circle transposon. Unlike other transposons (q.v.), helitrons lack terminal repeats and do not duplicate the insertion sites of their hosts. They carry 5′ TC and 3′ CTTR termini and are always inserted between nucleotides A and T of the host DNA. Helitrons were uncovered by an in silico analysis of genomic sequences from Arabidopsis, rice, and Caenorhabditis, and a helitron was later isolated as an insertion in a mutated Sh2 gene of Zea mays. See Chronology, 2001, Kapitonov and Jura; rolling circle.
Subjects: Genetics and Genomics.