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Abstract Detail

Molecular Ecology and Evolution

Geraci, Blake [1], Rodriguez , Roseana [2], Heo, Kweon [2], Chester, Michael [3], SOLTIS, PAMELA S. [4], Soltis, Douglas E. [5].

Chromosomal Variation in Synthetic Polyploids of Tragopogon miscellus and T. mirus (Asteraceae).

Polyploidy, or whole-genome duplication, has played a significant role in the evolution and diversification of plants in both recent and ancient times. Of particular interest are the initial phases of polyploidization in neopolyploid lineages. This study combines genomic in-situ hybridization (GISH) with mitotic squashes to explore the early phases of polyploid genome evolution in synthetic lines of Tragopogon miscellus and T. mirus, neopolyploids described by Ownbey in 1950. We attempt to distinguish parental contribution across multiple synthetic generations in order to expose the prevalence of aneuploidy and intergenomic translocations. We report on two cytological perspectives: one focused on the fourth generation, with the other spanning generations S1, S2, S4, and the presently growing S5. In the first study, fourth generation, T. miscellus plants were successfully hybridized using GISH probes which resulted in the following karyotypic patterns: 67% of the hybrids presented no intergenomic translocations, and 44% showed aneuploidy for one or more chromosomes. Of the latter, 50% of these exhibited compensated aneuploidy, in which the expected chromosome number (2n=24) is maintained through either monosomy-trisomy (1:3) or nullisomy-tetrasomy (0:4) of homeologous chromosomes. In the cross-generational study, our preliminary data hint that genomic consistencies are observed across generations. Should this stability be maintained, this may provide further support for previously observed chromosomal variation that showed stability of karyotypic abnormalities. Further study is needed, but cross-generational analyses will provide greater context on alterations in the neopolyploid's genetic stability and how this stability changes through time. Through further sampling of S4 lineages, we may be able to determine if similar changes occur between the synthetic and natural populations, thus bringing to light data on the repeatability of polyploid formation. 

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1 - Florida Museum Of Natural History, Dickinson Hall, University Of Florida, Gainesville, FL, 32611, USA
2 - University of Florida, Florida Museum of Natural History, Gainesville, FL, 32611, USA
3 - University of Oxford, Plant Sciences, South Parks Road, Oxford, OX1, 3RB, UK
4 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA
5 - University of Florida, Florida Museum of Natural History, Gainesville, FL, 32611


Presentation Type: Poster:Posters for Topics
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PME006
Abstract ID:587
Candidate for Awards:Genetics Section Poster Award

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