Grantee Research Project Results
1998 Progress Report: Ecosystem Monitoring via Genetic Diversity Surveys of Dandelions using VNTR multi-locus DNA probes
EPA Grant Number: R826602Title: Ecosystem Monitoring via Genetic Diversity Surveys of Dandelions using VNTR multi-locus DNA probes
Investigators: Rogstad, Steven , Keane, Brian
Institution: University of Cincinnati
EPA Project Officer: Hahn, Intaek
Project Period: July 14, 1998 through July 13, 2001 (Extended to July 13, 2003)
Project Period Covered by this Report: July 14, 1998 through July 13, 1999
Project Amount: $291,045
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:
New methodologies in molecular genetics may provide novel types of ecological indicators for monitoring the integrity of natural ecosystems and the sustainability of ecosystems that are affected by anthropogenic influences. One type of ideal ecological indicator would be an organism that grows in a wide variety of habitats that could be used easily to monitor for the presence of mutagens or anthropogenic factors that alter population genetics. Dandelions (Taraxacum officinale Weber; Asteraceae) are a model ecological indicator organism because: (1) dandelions have an extremely wide ecological amplitude, growing almost worldwide from sea-level to alpine biomes, and from the tropics to north-temperate habitats; (2) dandelions grow rapidly and populations can be manipulated easily and monitored; (3) it has been documented that a variety of pollutants can be sequestered in dandelion tissues; (4) dandelion seeds are produced asexually rendering the detection of mutations easy; and (5) we have generated preliminary data using variable-number-tandem-repeat (VNTR) DNA probes that suggest that mutation rates and population genetic diversity parameters can be analyzed successfully with dandelions. The specific hypothesis to be tested is: dandelions can be used as a sensitive ecological indicator species through comparative analyses of VNTR genetic markers because differences in mutation rates and/or population genetic structure can be detected between pollution impacted versus nonimpacted populations.Progress Summary:
Initial results demonstrate that very local populations harbor high genetic diversity comparable to sampling at larger scales suggesting that genotypes are spread widely due to very effective seed dispersal. In fact, we have found that certain clones may be widely distributed. Soil and dandelion tissue have been analyzed from more than 20 sites for metals, and we have selected 12 of these sites, covering a range of contamination, to compare dandelion mutation rates and population genetics. Dandelions have been sampled from these 12 sites: 6 relatively pristine sites versus 6 sites with chronic, high levels of contaminants. To determine whether rates of mutation differ between these two types of sites, leaf tissue from seed-producing plants and 8-10 seeds have been collected from each of 10 plants per site. Dandelion seeds are produced via agamospermy, a non-sexual process in which all seedlings from a maternal plant should be genetically identical to that maternal plant. Our preliminary results demonstrate that although the previous statement is true, a low level of mutation (approximately 0.005 percent of bands transmitted) is detectable. We are testing, by surveying the parent-to-offspring transmission of tens of thousands of VNTR markers, whether mutation rates differ between pristine versus contaminated sites. These markers also can be used to examine whether populations differ in genetic diversity.
We expect to determine whether VNTR markers in dandelions can be used as sensitive indicators of anthropogenic changes in population genetic diversity due to either altered mutation rates or stressor induced selection. If mutation rates or genetic diversity vary in correlation with increasing pollution, dandelions provide an easily utilized biomonitor to survey the ecological integrity and sustainability of a wide range of habitats across multiple spatial scales throughout the world.
Future Activities:
In addition to completing the above projects, we intend to grow dandelions in controlled media spiked with mixtures of common pollutants to investigate whether mutation rates increase with increasing pollutant concentrations. Further, we have initiated experiments to determine whether dandelions from the worst polluted sites have higher fitness when competing with dandelions from more pristine sites when both are grown in polluted and nonpolluted soils.Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 27 publications | 15 publications in selected types | All 13 journal articles |
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Keane B, Pelikan S, Toth GP, Smith MK, Rogstad SH. Genetic diversity of Typha latifolia (Typhaceae) and the impact of pollutants examined with tandem-repetitive DNA probes. American Journal of Botany 1999;86(9):1226-1238. |
R826602 (1998) R826602 (1999) R826602 (2000) R826602 (2001) R826602 (Final) |
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Lim HW, Pelikan S, Rogstad SH. Genetic diversity among populations and size classes of buckeyes (Aesculus: Hippocastanaceae) examined with multilocus VNTR probes. Plant Systematics and Evolution 2002;230(3-4):125-141. |
R826602 (1998) R826602 (1999) R826602 (2000) R826602 (2001) R826602 (Final) |
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Supplemental Keywords:
risk assessment, ecological effects, genetic polymorphisms, population responses., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Ecological Indicators, Ecological Risk Assessment, Ecosystem Protection, Ecology, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, Ecology and Ecosystems, Environmental Monitoring, genetic polymorphism, assessment methods, risk assessment, VNTR Multilocus DNA Probes, DNA, ecosystem indicators, multiple spatial scales, ecological exposure, anthropogenic stresses, dandelions, survey, genetic diversityRelevant Websites:
http://www.biology.uc.edu/faculty/rog/steve.htm
http://www.enn.com/enn-news-archive/1999/10/102899/cattail_6793.asp
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.