PARENT SESSION
Oral Session #64: Plant Population Ecology.
Presiding: S. Collins
Wednesday, August 7. 1:00 PM to 4:45 PM. Gila Meeting Room, TCC.

Mutation rates and leaf metal content in the common dandelion.

Keane, Brian^*,1, Collier, Matthew², Rogstad, Steve², ¹ Miami University - Hamilton, Hamilton, Ohio² University of Cincinnati, Cincinnati, Ohio

ABSTRACT- Human activity has resulted in elevated levels of many metal species in urban and industrial environments. Some forms of a number of metals are known or suspected mutagens and to evaluate the role of metal contaminates in generating DNA sequence mutations in chronically exposed individuals, populations of the common dandelion (Taraxacum officinale Weber, sensu lato; Asteraceae) in rural, urban and industrial areas were sampled. Dandelions reproduce asexually and mutation rates were estimated by identifying novel variable-number-tandem-repeat (VNTR) markers in the offspring of plants sampled in situ. Analysis of over 82,000 VNTR alleles in 1,200 offspring revealed an overall mutation rate of 0.007. For four metals (Cr, Fe, Mn and Ni), a significant positive relationship was found between mutation rate and dandelion leaf metal content. These mutations at VNTR loci may serve as convenient biomarkers for heritable genetic changes resulting from in situ exposure to environmental contaminants. In addition, the global distribution of the common dandelion, along with its ability to tolerate a wide range of environmental conditions, make this 'species' a particularly attractive candidate to evaluate for its value as a biological monitor of environmental metal contamination.

KEY WORDS: mutation, pollution, Taraxacum officinale, VNTR loci