Biology Department Name

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    Emily Mooney

    Photo image of Norris Muth

    Name: Emily E. Mooney

    Academic background:

    Doctor of Philosophy, Environmental and Evolutionary Biology, West Virginia University, Morgantown, WV, May 2007

    Bachelor of Science with Honors, Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY, December 2001

    Projects I am working on:

    The influence of plant genotype on herbivory, defense and herbivore response in sun an shade environments

    In August and September of 2007, we began a new investigation into the role of genetic variation in our research system. Microsatellite DNA variation has shown that L. benzoin populations 30km apart are genetically distinct. The neutral variation revealed by these markers is one aspect of genetic diversity within L. benzoin, and the other important aspect would be adaptive variation, i.e. genotypes have fitness differences. The fitness of a particular genotype can vary with environment, which can lead to differentiation between populations in dissimilar environments over time. In our system, the environmental factors that affect the fitness of L. benzoin are light and herbivory. Differences among genotypes in the effects of light and herbivory would reveal adaptive variation in L. benzoin.

    To assess adaptive variation in L. benzoin, we located 10 populations in eastern Pennsylvania across a broad geographic range. We measured light (photosynthetically-active radiation) and herbivory (proportion of total leaves with tissue missing) to measure extant environmental variation among populations. Forty juvenile plants (=1m in height) from each population were collected as bare roots and potted into 2 gal containers. Plants in pots were transplanted into four plots at the Graver Arboretum. The four plots were each divided into sun and shade subplots, which each contained five randomly-selected plants from each population source. We used data loggers to monitor light, temperature, soil moisture, and relative humidity in the subplots until plant senescence.

    Now that the plants are in place, undergraduate researchers can easily take on several projects that relate to the overall question. Upon initiation of growth in 2008, we will collect data on plant traits related to light environment and herbivory: chlorophyll concentration will be measured using a SPAD meter, several photosynthesis traits will be measured with a ADC Photosynthesis System and E. hortaria larvae will be used in bioassays.

     

    Phenotypic plasticity vs. genetic differentiation in response light environment and herbivory

    Phenotypic plasticity allows an individual to persist through environmental change or for a single genotype to occupy multiple environments. Nevertheless, genetic differentiation between environments is present in many plant species, as is evident from reciprocal transplant experiments and studies using molecular genetic markers. Our research objectives were to assess the roles of plasticity and genetic differentiation in L. benzoin, which allows populations to persist in sun and shade environment. We assessed differentiation between sun and shade habitats in populations of L. benzoin using 12 SSRs developed for this species from DNA libraries. We used a reciprocal transplant experiment to test for phenotypic plasticity in L. benzoin with respect to light environment. Specifically, plants of a single genotype were grown in sun and shade environments, and then half were switched into the contrasting light environment. Both before and after transplantation, we measured several plant traits related to herbivory, one factor responsible for fitness differences in L. benzoin between light environments. I am currently writing the manuscript describing the outcomes of these experiments for submission to a molecular ecology journal.

     

    Variation in herbivory-related traits among maternal families


    Spicebush is dioecious, making all the offspring of female plants half-siblings. The degree of resemblance among half-siblings for a particular trait can estimate the amount of additive genetic variance, i.e., the trait’s heritability. I collected nearly 1,000 seeds from over 25 maternal families to evaluate heritability of herbivory-related traits. Currently, the seeds are germinating after cold stratification for three months. In summer 2008, students from both chemistry and biology majors will design experiments to explore variation among the maternal families in plant traits.

    Contact info:

      Office/ Lab: 329 NSB
      Phone: (484) 664-3742
      Email: emooney@muhlenberg.edu

      Mailing address:
      Department of Biology
      Muhlenberg College
      Allentown, PA 18104


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This material is based upon work supported by the National Science Foundation under Grant No. 0442049. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.