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Our research focuses on the mechanisms and outcomes of phenotypic plasticity in life history, both within and across generations. Plasticity is thought to have evolved to maximize fitness, as it allows rapid response to environmental change without requiring genomic mutation. The controlling molecular mechanisms and adaptive and evolutionary consequences of plasticity are poorly understood, however. We are interested in knowing how environmental conditions cause changes in lifespan, reproductive mode and rate, and organismal health, and how these changes in life history shape individual and ecological outcomes.

Plasticity in response to environmental change may manifest both within and across generations. That is, the environment or physiology of a parent may affect the phenotype of its offspring without a change in genome. Our goals are to understand the molecular mechanisms, adaptive value, and evolutionary fitness consequences of within, inter-, and trans-generational plasticity in aging and life history strategy.

We use Brachionus rotifers -- microscopic, aquatic, invertebrate animals, composed of about 1000 cells – as the experimental system for our work. These zooplankton have many advantages as a model system to study aging and phenotypic plasticity. Easy laboratory culture and a short, two-week lifespan allow longitudinal studies at high levels of individual-level replication. Because Brachionus has direct development without a larval stage, life table experiments include the entire lifespan, unlike in other invertebrate models. Asexual reproduction allows experimentation on isogenic lines, and inducible sexual reproduction permits outcrossing and genetics. Transparency enables imaging of cellular morphology and processes. Genome and transcriptome sequencing shows that Brachionus rotifers have retained hundreds of human gene homologs that are absent from the genomes of established invertebrate models of aging. Thus, rotifers may be used to study many genes relevant to human aging that cannot be studied in other model systems.