Interactions between chromatin and transposable elements in rapid adaptation to environmental stress

Understanding how organisms adapt to the environmental perturbations, including those caused by human activity, is a key question in evolutionary biology.

Some organisms appear to adapt more rapidly than expected, and two factors predicted to contribute to this are environmentally sensitive epigenome regulation and transposable element (TE) activity under stress.

Recent molecular studies have shown how interactions between the epigenome and TEs can affect genome evolution in the fruitfly Drosophila melanogaster.

However, little is known about how these processes interact in natural populations, limiting our understanding of their role in population adaptation under environmental change.Environmentally sensitive interactions between the epigenome and TEs are underpinned by dynamic chromatin states regulating gene expression.

Understanding how chromatin varies across populations and how responsive it is to environmental change is key to evaluating the role of epigenome-TE interactions in adaptation.

Here we will measure natural variation in chromatin accessibility in different populations of D. melanogaster and look for associations between chromatin accessibility and polymorphic TEs.

Proximate mechanisms (RNA and chromatin responses to stress) and phenotypic outcomes (life history traits) will be measured over multiple generations.

Longer term evolutionary consequences will be measured in invasive and native populations of D. melanogaster and the more recently invading D. suzukii, and TEs associated with differential chromatin regulation in invasive populations will be validated using functional genomics techniques including CRISPR-Cas9.These data will reveal how interactions between chromatin states and TEs can shape adaptation over different organisational scales, from the molecular to the population-level, and across different temporal scales, including within-generation acclimation, transgenerational epigenetic change and long-term evolutionary change.