A transposition is a physical movement of genetic material (i.e., DNA) within a genome or the movement of DNA across genomes (i.e., from one genome to another). Because these segments of genetic material contain genes, transpositions resulting in changes of the loci (location) or arrangements of genes are mutations. Transposition mutations occur in a wide range of organisms. Transposons occur in bacteria-- and transposable elements have been demonstrated to operate in higher eukaryotic organisms, including mammalian systems.

Transposition mutations may only occur if the DNA being moved—termed the transposon--contains intact inverted repeats at its ends (terminus). In addition, functional tranposase enzymes must be present.

There are two types or mechanisms of transposition. Replicative transpositions involve the copying of the segment of section DNA to be moved (transposable element) before the segment is actually moved. Accordingly, with replicative transposition, the original section of DNA remains...