Research
Co-evolutionary dynamics between transposable elements and their hosts
Transposable elements make up a large portion of most genomes and dynamically shape their evolution. In Drosophila melanogaster and D. simulans around ~20% of the genome is transposable elements. Insects have elaborate mechanisms in place to suppress the transposition of transposable elements. Once a transposable element is suppressed, it cannot make more copies of itself thus their is a continual co-evolution between transposons and their hosts. Another way that transposons escape silencing is by invading the genomes of new species that do not yet have a defense against the transposon. Genomes are a mix of the degraded copies of old invasions that have been silenced and subject to mutation and new invasions that have not yet been silenced. These two processes are the focus of research in our lab - how genomes evolve to suppress transposons as transposons continue to evolve to escape silencing, and how transposons move into novel genomes. In the picture above the path of invasion of three transposable elements are shown, for example in the first panel the transposon Shellder moved from Central American drosophilids such as the willistoni and saltans group into D. simulans, where it spread to D. mauritiana, D. teissieri, and D. sechellia. Invasions such as these will become increasingly common as human movement brings new species into contact through climate change and commerce, which will significantly impact the evolution of insect genomes.
Transposable elements make up a large portion of most genomes and dynamically shape their evolution. In Drosophila melanogaster and D. simulans around ~20% of the genome is transposable elements. Insects have elaborate mechanisms in place to suppress the transposition of transposable elements. Once a transposable element is suppressed, it cannot make more copies of itself thus their is a continual co-evolution between transposons and their hosts. Another way that transposons escape silencing is by invading the genomes of new species that do not yet have a defense against the transposon. Genomes are a mix of the degraded copies of old invasions that have been silenced and subject to mutation and new invasions that have not yet been silenced. These two processes are the focus of research in our lab - how genomes evolve to suppress transposons as transposons continue to evolve to escape silencing, and how transposons move into novel genomes. In the picture above the path of invasion of three transposable elements are shown, for example in the first panel the transposon Shellder moved from Central American drosophilids such as the willistoni and saltans group into D. simulans, where it spread to D. mauritiana, D. teissieri, and D. sechellia. Invasions such as these will become increasingly common as human movement brings new species into contact through climate change and commerce, which will significantly impact the evolution of insect genomes.
Epitranscriptomics and the role of RNA modification in adaptation
Understanding the genotype to phenotype map is one of the most fundamental goals of modern science, and in most cases the genotype to phenotype map remains opaque. One potential explanation for this lack of a clear connection between gene expression and final phenotype are secondary processes that determine where mRNA is localized, how it is exported from the nucleus, how long it is stable, and whether or not it is translated. This can include different types of RNA modification, including alternative 3’ polyadenylation, alternative splicing, and epigenetic modification. My lab incorporates all three of these RNA processing mechanisms and seeks to understand their role in adaptation. Currently we are working to understand the specificity of epitranscriptomic modifications in different tissues of Drosophila. We are also working to understand the role of alternative splicing and polyadenylation in adaptation to environmental perturbations.
Understanding the genotype to phenotype map is one of the most fundamental goals of modern science, and in most cases the genotype to phenotype map remains opaque. One potential explanation for this lack of a clear connection between gene expression and final phenotype are secondary processes that determine where mRNA is localized, how it is exported from the nucleus, how long it is stable, and whether or not it is translated. This can include different types of RNA modification, including alternative 3’ polyadenylation, alternative splicing, and epigenetic modification. My lab incorporates all three of these RNA processing mechanisms and seeks to understand their role in adaptation. Currently we are working to understand the specificity of epitranscriptomic modifications in different tissues of Drosophila. We are also working to understand the role of alternative splicing and polyadenylation in adaptation to environmental perturbations.