Horizontal Transposon Transfer in Eukarya: detection, bias and perspectives
Gabriel Luz Wallau#,*
Pós Graduation in Animal Biodiversity, Universidade Federal de Santa Maria – RS – Brazil; Av. Roraima n° 1000 Santa Maria - RS - CEP: 97105-900. gabriel.wallau@gmail.com
*Corresponding author
Mauro Freitas Ortiz#
Pós Graduation in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul – RS – Brazil; Av. Bento Gonçalves, 9500 - Prédio 43323M Porto Alegre – RS – CEP: 91501-970. maurobios@gmail.com
Elgion Lucio Silva Loreto
Author Affiliations
Biology Department - Universidade Federal de Santa Maria - RS – Brazil; Av. Roraima n° 1000 Santa Maria - RS - CEP: 97105-900. elgion.loreto@pq.cnpq.br
Received February 10, 2012.
Revision received May 30, 2012.
Accepted July 5, 2012.
Abstract
The genetic similarity observed among species is normally attributed to the existence of a common ancestor. However, a growing body of evidence suggests that the exchange of genetic material is not limited to the transfer from parent to offspring but can also occur through horizontal transfer (HT). Transposable elements (TE) are DNA fragments with an innate propensity for HT; they are mobile and possess parasitic characteristics that allow them to exist and proliferate within host genomes. However, horizontal transposon transfer (HTT) is not easily detected, primarily because the complex TE life cycle can generate phylogenetic patterns similar to those expected for HTT events. The increasingly large number of new genome projects, in all branches of life, has provided an unprecedented opportunity to evaluate the TE content and HTT events in these species, though a standardized method of HTT detection is required before trends in the HTT rates can be evaluated in a wide range of eukaryotic taxa and predictions about these events can be made. Thus, we propose a straightforward hypothesis test that can be used by TE specialists and non-specialists alike to discriminate between HTT events and natural TE life cycle patterns. We also discuss several plausible explanations and predictions for the distribution and frequency of HTT and for the inherent biases of HTT detection. Finally, we discuss some of the methodological concerns for HTT detection that may result in the under- and overestimation of HTT rates during eukaryotic genome evolution.
Key words
horizontal transfer horizontal transmission transposable elements genome eukaryote evolution
© The Author(s) 2012. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
