Distribution and diversity of cytotypes in Dianthus broteri as evidenced by genome size variations

Abstract

Dianthus broteri shows the highest diversity of cytotypes known to date in the genus Dianthus. Moreover, some cytotypes present remarkable internal genome size variation. The evolution of the complex is discussed in terms of autopolyploidy, with primary and secondary contact zones.

Karyotype studies on Lycoris radiata populations from China

“…It occurs in 30-35% of the angiosperms, according to Stebbins (1971), whereas Coghlan et al (2005) estimated that 50-70% of all the species could be polyploid. Polyploidy has significant effects on the biochemistry, ecophysiology, and morphology of plants (Balao et al, 2009). Of the 25 populations surveyed, 15 were triploids.…”

“…This indicates an effect of minority cytotype exclusion and/or a widespread lack of gene-flow between the ploidy levels in nature. Balao et al (2009) used sample chromosome counts and flow cytometry to determine the overall genome size and the ploidy levels in 244 individuals belonging to 25 populations of Dianthus broteri. Extensive variation in chromosomes numbers (four levels of ploidy) was detected with each population reported to have a single ploidy level.…”

The effects of rapid desiccation on estimates of plant genome size

“…Of the eight studies listed above that used dried tissue to estimate genome size or make fine-scale comparisons, only four included a quantitative comparison between dry and fresh tissue. They reported differences ranging from less than 1.2% (Little et al 2007;Suda et al 2007;Balao et al 2009) to 12% (Cires et al 2009). Statistical tests in three studies produced contrasting results, with significant differences between dry and fresh tissue estimates in Šmarda (2006) and Cires et al (2009) but not in Balao et al (2009).…”

“…They reported differences ranging from less than 1.2% (Little et al 2007;Suda et al 2007;Balao et al 2009) to 12% (Cires et al 2009). Statistical tests in three studies produced contrasting results, with significant differences between dry and fresh tissue estimates in Šmarda (2006) and Cires et al (2009) but not in Balao et al (2009). In some cases, the effects of drying may have been confounded by other factors, for example, when different populations, DNA stains, or internal standards were used for the two tissue types.…”

“…This has included geographic surveys (e.g., Šmarda and Stančík 2006;Whittemore and Olsen 2011), phylogeographic studies (Eidesen et al 2007;Schönswetter et al 2007;Suda et al 2007;Popp et al 2008), and studies of the evolution of polyploid complexes (Harbaugh 2008;Balao et al 2009;Hersch-Green and Cronn 2009;Dušková et al 2010;Sonnleitner et al 2010). At the same time, the practical advantages of the method have led researchers to extend its use beyond ploidy analysis into reports of absolute genome size (e.g., Little et al 2007;Cires et al 2009;Whittemore and Olsen 2011) and fine-scale comparisons among populations or species of the same ploidy Popp et al 2008;Hersch-Green and Cronn 2009;Balao et al 2009;Dušková et al 2010).…”