Transposon

Definition

A mobile genetic element—also called a transposable element (TE)—that can move or copy itself to new locations within a genome. Class I transposons (retrotransposons) move via reverse transcription of an RNA intermediate; Class II transposons (DNA transposons) encode transposase and move via direct DNA excision and reinsertion. Transposons shape genome architecture, generate genetic diversity, and are exploited as mutagenesis and transformation tools in insects and other arthropods.

Etymology

From trans- (across, beyond) + Greek poson (part, portion), coined to describe genetic segments that change position.

Example

The P element, a Class II DNA transposon discovered in Drosophila melanogaster, enabled the development of germline transformation in fruit flies and remains foundational for insect genetic research; the piggyBac transposon, isolated from the moth Trichoplusia ni, is now widely used to insert genes into mosquito genomes for vector control studies.

Synonyms

• Transposable element
• TE
• mobile genetic element

Related Terms

• retrotransposon
• DNA transposon
• transposase
• insertion sequence
• Horizontal gene transfer
• genome evolution
• mutagenesis
• P element
• piggyBac

Usage Notes

Specialists often reserve 'transposon' for Class II DNA elements and use 'retrotransposon' for Class I, though 'transposable element' serves as the inclusive term. In entomology, transposon-based tools are distinguished from CRISPR by their ability to integrate large DNA payloads without double-strand break repair requirements. Some transposons are active only in germline cells, limiting their use in somatic mutagenesis screens.