Final Report: Intraspecies Genetic Diversity Measures of Environmental Impacts

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The objectives of this research project were to: (1) assess the suitability of randomly amplified polymorphic deoxyribonucleic acid (DNA)-polymerase chain reaction (RAPD-PCR) based measures of genetic diversity as an alternative to, or screening test for, U.S. Environmental Protection Agency (EPA) acute and chronic toxicity and bioaccumulation tests of ecological risk in a wide variety of resource types; and (2) characterize a set of organisms from a range of niches and trophic levels that are amenable to genetic diversity-based approaches that sensitively, rapidly, and inexpensively assay the impact of a wide range of environmental stressors. Hypotheses that have been addressed in this study include the following:

(1) RAPD-PCR based DNA profiles can provide reliable estimates of the genetic diversity of naturally occurring populations of a wide variety of organisms.

(2) Intraspecies estimates of genetic diversity based on multiple anonymous loci are correlated with currently used ecological indicators.

(3) Indices based on genetic diversity measurements from a site-specific suite of indicator species that span a variety of trophic levels and niches are more sensitive, robust, and reliable indicators of environmental risk than genetic diversity measures that rely upon a single organism.

(4) Measures of genetic diversity of local populations are less sensitive to spatial and seasonal influences than traditional methods of measuring environmental impacts.

(5) Potentially significant differences exist in the genetic diversity of organisms used in laboratory-based toxicity testing relative to those of naturally occurring populations.

(6) Genetic diversity measures are more effective guides to determining the overall impact of a wide range of environmental perturbations than any individual descriptor of physicochemical conditions, indigenous biodiversity estimates, toxicity, or bioaccumulation alone.

The genetic variability within a free-living population is directly related to its ability to adapt to its changing environment and to its ability to optimally and broadly utilize resources. Changes in a population's genetic diversity relative to that observed in a similar reference site have the potential to be reliable measures of the true impact of a wide variety of environmental insults. Taken as a whole, the studies develop and assess the utility of RAPD-PCR based measures of genetic diversity as a sensitive, rapid, and inexpensive alternative or supplement to traditional ecological indicators.


Submitted as the final report for EPA Grant Number: R826599