Transposable elements are DNA sequences that have the potential to move around a genome. Since a transposable element jumping into an essential gene is lethal, plants usually immobilise transposable elements by adding chemical marks to DNA (epigenetic modifications) that it recognises as transposable elements. Sections of DNA with a lot of transposable elements get compacted, which helps to stop the transposable elements moving.
My previous work (Wang, Weigel and Smith, 2013) has helped to demonstrate that epigenetic modifications in transposable elements are correlated with sections of DNA that get removed from the genome over time. However, we don’t know how this happens, or whether the DNA deletions of the epigenetic modifications come first. Therefore research in the lab will try to answer whether epigenetic modification do indeed drive deletions and other variations within plant genomes, and if so, then how.
Under severe stress, it may be advantageous for a plant to allow more rapid changes to its genome, in the hope that some of its progeny will be better adapted to high levels of a given stress. While other groups have shown that a single stress event can lead to changes in epigenetic modification and the occasional mobility of a transposable element, my lab is trying to understand the impact of long-term stress on genome evolution and adaptation.