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Abstract Detail


Genetics Section

Chester, Michael [1], Gallagher, Joseph [2], Symonds, V. Vaughan [3], Veruska C. Silva, Ana [4], Mavrodiev, Evgeny [5], Leitch , Andrew R. [6], Soltis, Pamela [7], Soltis, Douglas [1].

Population cytogenetics of a neoallopolyploid species, Tragopogon miscellus Ownbey (Asteraceae).

Tragopogon miscellus is one of only a few allotetraploid species known to have arisen within just the past few hundred years. This allotetraploid was first reported in 1950 and has formed multiple times from the diploids T. dubius and T. pratensis, which were introduced to the USA in the early 1900s. Thus, this model system provides natural populations in which to observe the early stages of polyploid evolution. Molecular analyses conducted to date suggest that T. miscellus is genetically unstable, with frequent losses of DNA detected. Preliminary cytological studies have also identified individuals with karyotypes that are not simply additive of the diploid progenitors. The cytology of T.miscellus was examined at the population level by sampling seeds collected from seven localities in the Palouse region of Washington and Idaho. Karyotypes were constructed from somatic metaphase chromosomes subjected to genomic in situ hybridization (GISH). Nuclear microsatellites were used to identify and delimit independently derived polyploidlineages of T. miscellus. Results show that many polyploid individuals have a non-additive karyotype, yet most of these aneuploids still have the euploid number of 24 chromosomes. Most dosage alterations appear compensated by putative homeologous chromosomes, resulting in monosomy-trisomy or nullisomy-tetrasomy. Significantly, monosomy-trisomy and nullisomy-tetrasomy have not been previously reported from nature. Both nullisomy and non-reciprocal translocations are likely to contribute to progenitor-specific DNA losses.

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1 - University of Florida, Department of Biology, Gainesville, FL, 32611, USA
2 - University of Florida, Department of Biology, Gainesville, Florida, 32611, USA
3 - Massey University, Private Bag 11222, Palmerston North, N/A, 4410, New Zealand
4 - Embrapa Coastal Tablelands, Aracaju, 49025, Brazil
5 - University Of Florida, Florida Natural History Museum, Florida Museum Of Natural History PO Box 117800, Gainesville, FL, 32611-7800, United States
6 - Queen Mary, University of London, School of Biological and Chemical Sciences, Mile End Road, E1 4NS, UK
7 - University of Florida, Department of Biology, FLMNH, Dickinson Hall, P.O. Box 117800, Gainesville, FL, 32611-7800, USA

Keywords:
Polyploidy
aneuploidy
genomic in situ hybridization.

Presentation Type: Oral Paper:Papers for Sections
Session: 39
Location: Lindell C/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 8:45 AM
Number: 39004
Abstract ID:560


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