Genetics: Published Articles Ahead of Print, published on July 1, 2007 as 10.1534/genetics.107.072751 Title: Concerted evolution of rDNA in recently formed Tragopogon allotetraploids is typically associated with an inverse correlation between gene copy number and expression. Authors: Roman Matyášek*, Jennifer A. Tate**,Yoong K. Lim† , Hana Šrubařová*, Jin Koh**, Andrew R. Leitch†, Douglas E. Soltis**, Pamela S. Soltis‡ , Aleš Kovařík* *Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i, Laboratory of Molecular Epigenetics, Královopolská 135, CZ-61265 Brno, Czech Republic **Department of Botany, University of Florida, Gainesville, FL 32611, USA †School of Biological Sciences, Queen Mary, University of London, E1 4NS, UK ‡Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA Sequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession nos: AM 493990 and AM 493995) 2 Running head: rDNA transcription in allotetraploids Key words: Tragopogon, rDNA expression, allopolyploidy, nucleolar dominance, gene silencing Correspondence: Ales Kovarik, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Laboratory of Molecular Epigenetics, Královopolská 135, CZ- 612 65 Brno, Czech Republic Tel.: +420-541517178, Fax: +420-541211293, E-mail:
[email protected] 3 ABSTRACT (175) We analyzed nuclear ribosomal DNA (rDNA) transcription and chromatin condensation in individuals from several populations of Tragopogon mirus and T. miscellus, allotetraploids that have formed repeatedly within only the last 80 years from T. dubius and T. porrifolius and T. dubius and T. pratensis, respectively. We identified populations with no (2), partial (2) and complete (4) nucleolar dominance.