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DEVELOPMENT OF AQUATIC MODELS FOR TESTING THE RELATIONSHIP BETWEEN GENETIC DIVERSITY AND POPULATION EXTINCTION RISK
Citation:
Markert, J, M J. Bagley, AND D Nacci. DEVELOPMENT OF AQUATIC MODELS FOR TESTING THE RELATIONSHIP BETWEEN GENETIC DIVERSITY AND POPULATION EXTINCTION RISK. Presented at Evolution 2004 Conference, Fort Collins, CO, June 26-30, 2004.
Impact/Purpose:
The objective of this task is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities (GPRA goal 4.5.2). Specifically, this subtask aims to evaluate methods for the measurement of:
fish and invertebrate community composition, especially for morphologically indistinct (cryptic) species
population genetic structure of aquatic indicator species and its relationship to landscape determinants of population structure (to aid in defining natural assessment units and to allow correlation of population substructure with regional stressor coverages)
genetic diversity within populations of aquatic indicator species, as an indicator of vulnerability to further exposure and as an indicator of cumulative exposure
patterns of temporal change in genetic diversity of aquatic indicator species, as a monitoring tool for establishing long-term population trends.
Description:
The relationship between population adaptive potential and extinction risk in a changing environment is not well understood. Although the expectation is that genetic diversity is directly related to the capacity of populations to adapt, the statistical and predictive aspects of this relationship in real populations are not well known. From a conservation perspective, it is useful to understand this relationship so that genetic data may be incorporated into population viability models which traditionally rely on demographic and ecological data. Here we present an experimental design using the freshwater amphipod species Hyalella azteca and the marine mysid Americamysis bahia. These organisms differ with respect to demographic and biogeographic constraints, and present a useful contrast with Drosophila and Tribolium laboratory models. The design involves creating inbred lines from diverse native populations. Individuals from each inbred line will be combined to form "synthetic" populations from either three or six randomly selected inbred lines in order to generate experimental populations with controlled levels of genetic diversity, and the entire set will be replicated ten times. The adaptive capacity of these "synthetic" and inbred populations will be compared to that of native populations and an "admixed" population containing genes from all sampled populations. Differences in population extinction times will be interpreted as differences in population adaptive capacity, and provide data for formal population viability analyses (PVA's). By experimentally manipulating levels of population genetic diversity, we will be able to formally assess both the relationship between genetic diversity and population viability in an increasingly hostile environment and also determine the statistical efficiency of various classes of genetic markers.