Insights & Perspectives
Do miRNAs have a deep evolutionary history?
Article first published online: 30 JUL 2012
Copyright © 2012 WILEY Periodicals, Inc.
Volume 34, Issue 10, pages 857–866, October 2012
How to Cite
Tarver, J. E., Donoghue, P. C. J. and Peterson, K. J. (2012), Do miRNAs have a deep evolutionary history?. Bioessays, 34: 857–866. doi: 10.1002/bies.201200055
- Issue published online: 13 SEP 2012
- Article first published online: 30 JUL 2012
- microRNA evolution;
The recent discovery of microRNAs (miRNAs) in unicellular eukaryotes, including miRNAs known previously only from animals or plants, implies that miRNAs have a deep evolutionary history among eukaryotes. This contrasts with the prevailing view that miRNAs evolved convergently in animals and plants. We re-evaluate the evidence and find that none of the 73 plant and animal miRNAs described from protists meet the required criteria for miRNA annotation and, by implication, animals and plants did not acquire any of their respective miRNA genes from the crown ancestor of eukaryotes. Furthermore, of the 159 novel miRNAs previously identified among the seven species of unicellular protists examined, only 28 from the algae Ectocarpus and Chlamydomonas, meet the criteria for miRNA annotation. Therefore, at present only five groups of eukaryotes are known to possess miRNAs, indicating that miRNAs have evolved independently within eukaryotes through exaptation of their shared inherited RNAi machinery.