Transposable element

Definition

A mobile DNA sequence capable of changing position within a genome through excision, insertion, or replication mechanisms. Class I elements (retrotransposons) mobilize via an RNA intermediate and reverse transcription, amplifying copy number; Class II elements (DNA transposons) move as DNA via transposase-mediated cut-and-paste or related mechanisms. TEs constitute substantial fractions of many arthropod genomes, influence gene regulation, drive mutational load, and serve as powerful molecular markers for phylogeography and population structure.

Etymology

From Latin transponere (to place across) + element, reflecting the capacity to relocate within the genetic material.

Example

The mariner/Tc1 superfamily of DNA transposons has been independently domesticated in multiple insect lineages and is exploited in transgenic technology: the piggyBac element from the cabbage looper Trichoplusia ni enables stable germline transformation in mosquitoes, beetles, and other non-model arthropods by inserting TTAA target sequences without requiring host factors.

Synonyms

• Transposon
• mobile genetic element

Related Terms

• retrotransposon
• DNA transposon
• transposase
• genome size
• Horizontal gene transfer
• piRNA pathway
• hybrid dysgenesis
• P element

Usage Notes

Specialists distinguish TE mobility mechanisms carefully: 'jumping gene' is informal; 'retrotransposon' and 'DNA transposon' specify Class I versus Class II. Copy number varies enormously—TEs comprise ~50% of some lepidopteran genomes but under 1% in certain ant lineages. Activity is often suppressed by host small RNA pathways (piRNA, siRNA). Context matters for 'transposon' versus 'transposable element': the former sometimes excludes non-autonomous derivatives, though usage overlaps.