Our model system:
Our 'work-horse' model organism is the nematode Pristionchus pacificus, which develops one of two possible mouth forms in adults, depending on conditions experienced as juveniles: a narrow stenostomatous morph with one denticle, or a wide eurystomatous morph with two "teeth". Stenostomatous morphs are obligate bacteriavores, while the eurystomatous morph can predate on other nematodes. In nature the developmental decision is effected by adult pheromones (Bose et al., 2012, Werner et al. 2018), while in the lab we can utilize simple culture conditions to modulate mouth form preference (Werner et al. 2017).
The epigenetics of phenotypic plasticity
Epigenetic modifications that regulate cellular plasticity are prime candidates to convey environmental information into ideally suited organismal phenotypes. However, their potential contributions to phenotypic plasticity are still largely unknown. We aim to (1) uncover the identity of epigenetic information carriers that contribute to alternative phenotypes, and (2) determine how these modifications communicate environmental information into transcriptional, and ultimately physiological and morphological phenotypes.
The evolution of regulatory elements
We recently discovered that 'new' genes, otherwise known as taxon restricted, or 'orphan' genes, have distinct chromatin signatures at their 5' ends - resembling enhancers, rather than traditional promoters. We are interested in examining the generality of this phenomenon, and the process of enhancer-promoter evolutionary turnover.
Werner, M.S., Sieriebriennikov, B., Prabh, N., Loschko, T., Lanz, C., and Sommer, R.J. (2018). Young genes have distinct gene structure, epigenetic profiles, and transcriptional regulation. Genome Res. 28, 1675–1687. https://genome.cshlp.org/content/28/11/1675.full.html
Extremophile nematodes and Great Salt Lake ecology
We have discovered what appear to be new species of halophilic nematodes in Gilbert Bay of the Great Salt Lake. At salinities up 20%, this is among the most saline environment from which nematodes have ever been found. Who are they, where did they come from, and how do they survive there? Current projects are investigating the alpha-taxonomy and systematics of these worms, their ecology in the GSL, and how they can survive in its extreme hypersaline conditions.
Our research program will interrogate how animals incorporate environmental input into changes in phenotype - including morphology, physiology, and behavior. Beyond the fundamental principles of development and evolution, our results may shed light on how we learn and form memories, and how our bodies respond to diet and exercise. Furthermore, aging and cancer are associated with epigenetic mechanisms of cellular plasticity. Some promising chemotherapeutic drugs affect this cellular plasticity, although the molecular targets and secondary consequences are poorly understood. A long term goal of our lab is to use experimentally tractable model organisms to identify epigenetic mechanisms that shed light on human health and development.