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Abstract Detail



Genetics Section

McCann, Jamie L. [1], Stuessy, Tod F. [1], Villasenor, Jose L. [2], Weiss-Schneeweiss, Hanna [1], Schneeweiss, Gerald [1].

Origin and genomic evolution of polyploids in Melampodium sect. Serratura (x = 12; Asteraceae).

Polyploidy is an important factor in plant evolution, where it is often accompanied by hybridization to form allopolyploids. Inference of the origins of polyploids and identification of parental taxa is a prerequisite for understanding their subsequent genome and chromosome evolution. The genus Melampodium (Asteraceae) comprises a number of allopolyploid species, some of which have been hypothesized to share the same parental origin. This genus, therefore, presents an excellent system in which to investigate the dynamics of genomic change in polyploids in general, and polyploids sharing parental taxa in particular. In this study, several nuclear (ITS, 5S rDNA NTS, low-copy PgiC) and plastid (matK, psbA) markers are used to test the previously proposed hypotheses on the origins of polyploids in section Serratura (x = 12), which includes three diploids (2n = 2x = 24), one autopolyploid cytotype with a secondary dysploid chromosome number reduction (2n = 4x − 2 = 46), and three allopolyploids (2n = 4x = 48). The phylogenetic analysis of all molecular markers, particularly two paralogues of the nuclear gene PgiC, allows unambiguous identification of maternal and paternal diploid taxa involved in the origin of the allopolyploid species. Ribosomal DNA loci number, interpreted in a phylogenetic framework, reveals patterns of loss or retention of parental loci among allopolyploid species. Evidence is provided for the independent evolution of different allopolyploid species from the same diploid species.

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1 - University of Vienna, Systematic And Evolutionary Botany, Rennweg 14, Wien, N/A, A-1030, Austria
2 - Universidad Nacional Autónoma de México, Botánica, México, DF, 04510, México

Keywords:
Allopolyploid origin
Melampodium
genome evolution
rDNA
Low-copy nuclear gene.

Presentation Type: Oral Paper:Papers for Sections
Session: 21
Location: Marlborough B/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 8:45 AM
Number: 21001
Abstract ID:362
Candidate for Awards:None


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