On the habits of transposons: Dissociation mapping in maize and megabase sequencing in wheat reveal site preferences, distribution, and evolutionary history

Abstract

Transposable elements (TEs) have surprised and intrigued biologists since their discovery, and our understanding of the roles of transposons in genome dynamics has continued to evolve in the elapsed years. Continued research on transposons and insights from genome sequencing have banished the "junk" designation and produced a more nuanced view of the interaction between transposons of different types and their host genomes. Specifically, it was found that the retrotransposons (REs), which move through an RNA intermediate, and the DNA TEs can produce strikingly different effects on genome dynamics. Although transposons can create adaptive variation, they also adversely affect the host genome by causing mutations and genome expansion. To mitigate these effects, plants typically use epigenetic control to limit element replication by silencing the elements. In this issue, two papers examine different aspects of transposon biology and its role in genome evolution: one by examining the locations of thousands of new insertions of the maize (Zea mays) Dissociation (Ds) element, and the other by profiling the distribution of transposons and genes in megabase tracts of sequence from the tremendously expanded and repeat-rich wheat (Triticum aestivum) genome. © 2010 American Society of Plant Biologists.