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

Autori
Frajman, Božo ; Rešetnik, Ivana ; Weiss-Schneeweiss, Hanna ; Ehrendorfer, Friedrich ; Schönswetter, Peter

Izvornik
Bmc evolutionary biology (1471-2148) 15 (2015); 140-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
chromosome numbers; cytotype diversity; genome downsizing; genome size; Knautia; polyploidy

Sažetak
Polyploidisation 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. Genome 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 hexaploid species are limited to the Balkan and Iberian Peninsulas and the Alps. We 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.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA