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A MULTI-LOCUS, MULTI-TAXA PHYLOGEOGRAPHICAL ANALYSIS OF GENETIC DIVERSITY
Citation:
Sloss, B. L. AND M J. Bagley. A MULTI-LOCUS, MULTI-TAXA PHYLOGEOGRAPHICAL ANALYSIS OF GENETIC DIVERSITY. Presented at Southeastern Association of Fish and Wildlife Agencies, Louisville, KY, October 13-17, 2001.
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:
In addition to measuring spatial patterns of genetic diversity, population genetic measures of biological resources should include temporal data that indicate whether the observed patterns are the result of historical or contemporary processes. In general, genetic measures focused solely on allele frequencies are poor indicators of temporal processes. The use of allele genealogies and allele frequency data permit the inference of temporal processes from one-time samples of spatial patterns. The value of this phylogeographic approach has been clearly demonstrated with mitochondrial DNA data. However, reliance on a single locus for any genetic study is error prone. We are developing 12-16 EPIC (Exon-Primed, Intron-Crossing) primers designed to amplify homologous intron regions within teleost genomes. These loci will aid in population analyses, including stock identification, estimates of gene flow, effective population size, and effects of environmental change. In addition, multi-species assessment of homologous markers permits a more accurate assessment of patterns of biodiversity and the condition of biological resources across a wide geographical area. Intron regions from eight nuclear genes (c-myc proto-oncogene, K-ras, Pax transcription factor, 40S ribosomal protein 24, GTPase, ependymin, and alpha crystallin) have been amplified and cloned for Semotilus atromaculatus (creek chub), Campostoma anomalllum (central stoneroller), Catostomus commersoni (white sucker), Ameiurus nebulosus (brown bullhead) and/or Lepomis cyanellus (green sunfish). These loci will be combined with mtDNA data to analyze the distribution of genetic diversity in creek chub, central stoneroller, and white sucker within USEPA's Mid-Atlantic Integrated Assessment (MAIA) study area.