Cytotype diversity and genome size variation in Knautia (Caprifoliaceae, Dipsacoideae)

BMC Evolutionary Biology

Research Article

Hanna Weiss-Schneeweiss¹  Friedrich Ehrendorfer¹  Ivana Rešetnik²  Peter Schönswetter³  Božo Frajman³ 

[1] Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030, Vienna, Austria;Faculty of Science, University of Zagreb, Marulićev trg 20/II, HR-10000, Zagreb, Croatia;Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020, Innsbruck, Austria;

关键词: Chromosome numbers;    Cytotype diversity;    Genome downsizing;    Genome size;    Knautia;    Polyploidy;   

DOI  :  10.1186/s12862-015-0425-y

 received in 2015-02-10, accepted in 2015-06-26,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundPolyploidisation is one of the most important mechanisms in the evolution of angiosperms. As in many other genera, formation of polyploids has significantly contributed to diversification and radiation of Knautia (Caprifoliaceae, Dipsacoideae). Comprehensive studies of fine- and broad-scale patterns of ploidy and genome size (GS) variation are, however, still limited to relatively few genera and little is known about the geographic distribution of ploidy levels within these genera. Here, we explore ploidy and GS variation in Knautia based on a near-complete taxonomic and comprehensive geographic sampling.ResultsGenome size is a reliable indicator of ploidy level in Knautia, even if monoploid genome downsizing is observed in the polyploid cytotypes. Twenty-four species studied are diploid, 16 tetraploid and two hexaploid, whereas ten species possess two, and two species possess three ploidy levels. Di- and tetraploids are distributed across most of the distribution area of Knautia, while hexaploids were sampled in the Balkan and Iberian Peninsulas and the Alps.ConclusionsWe show that the frequency of polyploidisation is unevenly distributed in Knautia both in a geographic and phylogenetic context. Monoploid GS varies considerably among three evolutionary lineages (sections) of Knautia, but also within sections Trichera and Tricheroides, as well as within some of the species. Although the exact causes of this variation remain elusive, we demonstrate that monoploid GS increases significantly towards the limits of the genus’ distribution.

【 授权许可】

Unknown   
© Frajman et al. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.