Transposable Elements: Major Players in Shaping Genomic and Evolutionary Patterns

Transposable elements (TEs) are ubiquitous genetic elements, able to jump from one location of the genome to another, in all organisms. For this reason, on the one hand, TEs can induce deleterious mutations, causing dysfunction, disease and even lethality in individuals. On the other hand, TEs can increase genetic variability, making populations better equipped to respond adaptively to environmental change. To counteract the deleterious effects of TEs, organisms have evolved strategies to avoid their activation. However, their mobilization does occur. Usually, TEs are maintained silent through several mechanisms, but they can be reactivated during certain developmental windows. Moreover, TEs can become de-repressed because of drastic changes in the external environment. Here, we describe the 'double life' of TEs, being both 'parasites' and 'symbionts' of the genome. We also argue that the transposition of TEs contributes to two important evolutionary processes: the temporal dynamic of evolution and the induction of genetic variability. Finally, we discuss how the interplay between two TE-dependent phenomena, insertional mutagenesis and epigenetic plasticity, plays a role in the process of evolution.

Automated summary

Transposable elements (TEs) are genetic elements that can move within the genome, causing both deleterious mutations and increasing genetic variability. Organisms have developed strategies to prevent their activation, but TEs can still be activated during certain developmental windows or in response to drastic changes in the environment. TEs have a dual role as both parasites and symbionts of the genome, contributing to the temporal dynamics of evolution and the induction of genetic variability. Insertional mutagenesis and epigenetic plasticity also play a role in the evolutionary process.