Certner_2015_EcolEvol

This MS Excel file contains all the primary data and some partial results

List of morphometric characters used in distance-based morphometric analyses.

<p>List of morphometric characters used in distance-based morphometric analyses.</p

Principal component analysis of <i>Diphasiastrum</i> taxa from Northern Europe.

<p>PCA of 57 individuals based on 16 vegetative morphological characters (the first and second ordination axis explain 29.0% and 23.9% of total variation, respectively) illustrates different pattern of morphological variation in Northern Europe. Genome size (values in pg DNA) is passively projected in the diagram using a local regression (loess) model. Individual accessions are designated by different symbols based on their independent taxonomic determination according to regional keys and floras (i.e. a passive illustrative projection). Outlaying <i>D. alpinum</i> accession (0.408, 0.198) is an example of extremely shaded ecotype (see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099552#pone.0099552.s001" target="_blank">Figure S1</a>).</p

Distribution of absolute genome sizes of Diphasiastrum samples.

<p>Absolute genome sizes of <i>Diphasiastrum</i> individuals assigned to six European taxa in Central (A; 561 individuals, range 4.73–7.80 pg) and Northern (B; 63 individuals, range 5.13–7.33 pg) Europe. Different colors denote species as independently cross-check determined using several regional keys and floras (i.e. a passive illustrative projection; see Methods for details).</p

Continuous Morphological Variation Correlated with Genome Size Indicates Frequent Introgressive Hybridization among <i>Diphasiastrum</i> Species (Lycopodiaceae) in Central Europe

<div><p>Introgressive hybridization is an important evolutionary process frequently contributing to diversification and speciation of angiosperms. Its extent in other groups of land plants has only rarely been studied, however. We therefore examined the levels of introgression in the genus <i>Diphasiastrum</i>, a taxonomically challenging group of Lycopodiophytes, using flow cytometry and numerical and geometric morphometric analyses. Patterns of morphological and cytological variation were evaluated in an extensive dataset of 561 individuals from 57 populations of six taxa from Central Europe, the region with the largest known taxonomic complexity. In addition, genome size values of 63 individuals from Northern Europe were acquired for comparative purposes. Within Central European populations, we detected a continuous pattern in both morphological variation and genome size (strongly correlated together) suggesting extensive levels of interspecific gene flow within this region, including several large hybrid swarm populations. The secondary character of habitats of Central European hybrid swarm populations suggests that man-made landscape changes might have enhanced unnatural contact of species, resulting in extensive hybridization within this area. On the contrary, a distinct pattern of genome size variation among individuals from other parts of Europe indicates that pure populations prevail outside Central Europe. All in all, introgressive hybridization among <i>Diphasiastrum</i> species in Central Europe represents a unique case of extensive interspecific gene flow among spore producing vascular plants that cause serious complications of taxa delimitation.</p></div

A partial least squares correlation between the shape and genome size.

<p>PLS analysis of <i>Diphasiastrum</i> taxa (correlation coefficient is 0.67) confirmed correlation between the shape the ventral side of the stem and genome size. A taxonomic determination based on regional keys and floras is passively projected using differently colored symbols. Individual specimens are shown to highlight the shape at the upper and lower genome size extremes.</p

Principal component analysis of <i>Diphasiastrum</i> taxa.

<p>PCA of 466 individuals from Central Europe based on 16 vegetative morphological characters (the first and second ordination axis explain 33.4% and 27.2% of total variation, respectively). Genome size (values in pg DNA) is passively projected in the diagram using a local regression (loess) model. Individual accessions are designated by different symbols based on their independent taxonomic determination according to regional keys and floras (i.e. a passive illustrative projection).</p

Variation in the shape of the ventral side of the stem.

<p>Relative warp analysis of 313 <i>Diphasiastrum</i> taxa accessions based on 37 landmarks (the first and second ordination axis explain 45.7% and 12.2% of total variation, respectively). Genome size (values in pg DNA) is passively projected in the diagram using a local regression (loess) model.</p

Characters used in morphometric analyses.

<p>Characters localized on the ventral and dorsal side of the stem of <i>Diphasiastrum</i> taxa. The lines indicate variables measured for numerical morphometrics; the points denote landmarks (fulfilled dot) and sliding semilandmarks (striped dot) used in geometric morphometry.</p

Bringing Together Evolution on Serpentine and Polyploidy: Spatiotemporal History of the Diploid-Tetraploid Complex of <em>Knautia arvensis</em> (Dipsacaceae)

<div><p>Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb <em>Knautia arvensis</em> (Dipsacaceae), a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of <em>K. arvensis</em> allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary ‘dead-ends’ but rather dynamic systems with a potential to further influence the surrounding populations, e.g., via independent polyplodization and hybridization. The complex eco-geographical pattern together with the incidence of both primary and secondary diploid-tetraploid contact zones makes <em>K. arvensis</em> a unique system for addressing general questions of polyploid research.</p> </div