Molecular Ecology and Evolution
Wright, Kirsten , Pires, J. Chris , Madlung, Andreas .
Chromosomal Analysis of Natural Allopolyploid Arabidopsis suecica.
Polyploidy is a eukaryotic phenomenon common to plants that serves as an evolutionary mechanism for speciation. Diploid species undergo polyploidization through genome duplication (autopolyploidy) or by the hybridization of genomes from two or more distinct progenitor species (allopolyploidy). Aneuploidy arises when offspring possess extra or fewer chromosomes than their progenitors. Over successive generations, changes in chromosomal number and rearrangements can lead to speciation or differentiation of ecotypes or varieties within a species. Using fluorescent in situ hybridization (FISH) with species-specific centromeric probes, chromosomes in allopolyploids can be traced back to their progenitor species.
Here we investigate the chromosomal composition of 13 accessions of the natural allopolyploid Arabidopsis suecica to determine if aneuploidy plays a role in the speciesí evolution. Such chromosomal change could potentially lead to evolutionary radiation of populations into separate species. Interestingly, our results suggest that one of the two parental species (A. arenosa) displays a strong tendency towards mitotic errors and aneuploid somatic cells, while the other parent (A. thaliana) shows consistently normal mitosis. We further show that established allopolyploids of these parents display aneuploidy in somatic cells in each tested accession of A. suecica, albeit at a much reduced degree. We conclude that aneuploidy in the allopolyploid A. suecica may have the potential to lead to novel cytotypes accelerating evolutionary radiation. The reason for the chromosomal instability may be the influence of inherited mitotic difficulties that we observed in the parent species A. arenosa, rather than the result of allopolyploidization.
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1 - University of Puget Sound, Biology, 1500 N Warner, CMB 1088, Tacoma, WA, 98416, USA
2 - University of Missouri, Biological Sciences, 1201 Rollins Road, 311 Life Sciences Center, Columbia, Missouri, 65211, USA
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM