Transposition is a multistep process in which a transposable element DNA sequence moves from its original genetic location to a new site. Early steps in this process include the formation of a transposition complex in which the end sequences of the transposable element are brought together in a structurally precise fashion through the action of the element-encoded transposase protein and the cl...

There is much debate about the significance of transposable elements for the organisms that host them, and the nature of the forces responsible for maintaining them in the host population. Recent theoretical and experimental studies of the population biology of transposons have shed light on these controversies.

Protective mechanisms based on RNA silencing directed against the propagation of transposable elements are highly conserved in eukaryotes. The control of transposable elements is mediated by small noncoding RNAs, which derive from transposon-rich heterochromatic regions that function as small RNA-generating loci. These clusters are transcribed and the precursor transcripts are processed to gene...

The idea that some genetic factors are able to move around chromosomes emerged more than 60 years ago when Barbara McClintock first suggested that such elements existed and had a major role in controlling gene expression and that they also have had a major influence in reshaping genomes in evolution. It was many years, however, before the accumulation of data and theories showed that this latte...

While evolution is often understood exclusively in terms of adaptation, innovation often begins when a feature adapted for one function is co-opted for a different purpose, such aswhen feathers originally adapted for insulation became used for flight. Co-opted features are called exaptations. Transposable elements are often viewed as molecular parasites, yet they are frequently the source of ev...

The P, hobo, Hermes, Minos and mariner transposable elements have been successfully used as gene vectors to achieve genetic transformation of Drosophila melanogaster. The hobo transposable element of D. melanogaster, a member of the hAT family of transposable elements, can also transpose in other dipteran species including the house fly Musca domestica and the Queensland fruit fly, Bactrocera t...

A series of molecular events will explain how genetic elements can transpose from one DNA site to another, generate a short oligonucleotide duplication at both ends of the new insertion site, and replicate in the transposition process. These events include the formation of recombinant molecules which have been postulated to be intermediates in the transposition process. The model explains how t...