The struggle for life of the genome's selfish architects

Abstract

Transposable elements (TEs) were first discovered more than 50 years ago, but were totally ignored for a long time. Over the last few decades they have gradually attracted increasing interest from research scientists. Initially they were viewed as totally marginal and anecdotic, but TEs have been revealed as potentially harmful parasitic entities, ubiquitous in genomes, and finally as unavoidable actors in the diversity, structure, and evolution of the genome. Since Darwin's theory of evolution, and the progress of molecular biology, transposable elements may be the discovery that has most influenced our vision of (genome) evolution. In this review, we provide a synopsis of what is known about the complex interactions that exist between transposable elements and the host genome. Numerous examples of these interactions are provided, first from the standpoint of the genome, and then from that of the transposable elements. We also explore the evolutionary aspects of TEs in the light of post-Darwinian theories of evolution.

Reviewers: This article was reviewed by Jerzy Jurka, Jürgen Brosius and I. King Jordan. For complete reports, see the Reviewers' reports section.

Figure 1

TE contents in various different sequenced species: genome size are in Mb. TE percentages are shown within parentheses. References can be found in Additional File 1.

Figure 2

The different levels of TE utilization by the genome. TE sequences (green and blue) may contribute to gene regulatory regions (yellow, thin rectangles) or coding sequences (large rectangles). Small portions or almost entire elements can be exapted, which can result in new regulations or new genes.

Figure 3

Illustration of the similarities between the theoretical dynamics of autonomous/non-autonomous TE copies (top row) and prey-predator models (bottom row). The transposition model is described in Le Rouzic & Capy 2006. See Additional File 1 for more details about equation models.