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(78-04) The Dragonfly: An Effective Genetic Biomarker of Environmental Pollution. Schlueter, Mark*,1, Hellbach, Emily2, Carter, Robert2, Welt, Marc2, 1 Xavier University of Louisiana, New Orleans, Louisiana2 Xavier University of Louisiana, New Orleans, Louisiana ABSTRACT- Currently, there are limited insect biomarkers with field applications, even though insects play key roles in most terrestrial and freshwater ecosystems. Most pollutants and toxicants occur at the highest concentrations in the soil or aquatic sediment due to solubility and settling; however most current biomarker species spend little or no time in these areas. The development of a biomarker species that resides a significant portion of its life span in the sediment may be a more sensitive indicator of environmental health and stability. Dragonflies are an excellent example of an insect species whose larvae spends one or more years in the aquatic sediment. The main goal of the following study is to investigate the potential of the dragonfly as a new biomarker species of pollution. Dragonflies show a high level of genetic diversity as measured by allozymes (protein phenotypes) and by DNA fingerprinting. Allozyme allele frequencies were examined to determine if these characteristics were related to environmental quality. Population genetic structure (allele frequencies) of several populations of a common dragonfly species, the green pondhawk (Erythemis simplicicollis), were compared and contrasted. Populations were sampled from "polluted" sites (e.g. heavy metals, petroleum) and "clean" sites. Differences in allele frequencies were detected in the populations. These differences may be related to the toxicants present in the environment. DNA fingerprinting (RAPD markers) was able to identify individuals as well as separate populations. Allozyme data show that selection for specific phenotypes are related to environmental pollution. This was illustrated by comparisons of allozyme phenograms to genomic population phenograms. These differences suggest that the phenotypic (allozyme) data from dragonflies may serve as an effective biomarker of environmental health. Key words: Erythemis simplicicollis, Insect, Allozyme, Bioindicator |
