Based in part on the previous version of this eLS article ‘Evolutionary History and Impact of Human DNA Transposons’ (2008) by Cédric Feschotte.
Evolutionary History and Impact of Human DNA Transposons
Published Online: 18 OCT 2013
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Feschotte, C. and McCormick, J. 2013. Evolutionary History and Impact of Human DNA Transposons. eLS. .
- Published Online: 18 OCT 2013
Deoxyribonucleic acid (DNA) transposons are mobile elements that move via a DNA intermediate. The (haploid) human genome harbours more than 300 000 DNA transposon copies, accounting for approximately 3% of the total genomic DNA. Nearly one-third of these elements are specific to the primate lineage, but there is no evidence for transposition activity within the past 40 million years. However, there is growing evidence that DNA transposons have contributed in shaping the current genome architecture of humans and have been a recurrent source of new regulatory and coding DNA throughout mammalian evolution. Notably, more than 50 human genes are currently known to descend from transposase sequences recycled to perform diverse cellular functions.
DNA (or class 2) transposons represent a minority of the mobile genetic elements populating mammalian genomes, but still account for more DNA in our genome than all protein-coding sequences.
DNA transposition was once very active in mammals and has generated approximately 100 000 primate-specific insertions in our genome.
DNA transposon germline activity suddenly ceased ∼40 million years ago in the human lineage, but has persisted in other mammalian lineages – most prominently and recently in vesper bats.
Despite the lack of current transposition activity, DNA transposons may still be promoting genomic rearrangements, including recurrent ectopic recombination events associated with pathologies.
Like many other mobile elements in the human genome, some DNA transposons have been incorporated into the regulatory apparatus of the genome through the donation of enhancers and regulatory elements modulating adjacent gene expression.
Transposases have been a source of coding sequences for the assembly of several new genes during vertebrate evolution, including at least 50 genes in the human genome. The function of most human transposase-derived genes remains unknown or poorly understood, but some have emerged as key regulators for a variety of cellular processes.
- transposable elements;
- selfish DNA;
- noncoding DNA;
- new genes;
- genome evolution