Evolutionary importance of the relationship between cytogeography and climate: New insights on creosote bushes from North and South America

Relationships between genome size and environmental variables suggest that DNA content might be adaptive and of evolutionary importance in plants. The genus Larrea provides an interesting system to test this hypothesis, since it shows both intra- and interspecific variation in genome size. Larrea has an amphitropical distribution in North and South American deserts, where it is most speciose. Larrea tridentata in North America shows a gradient of increasing autopolyploidy; while three of the four studied South American species are diploids, Larrea divaricata, Larrea nitida, Larrea ameghinoi, and the fourth is an allopolyploid, Larrea cuneifolia. We downloaded available focal species’ georeferenced records from seven data reservoirs. We used these records to extract biologically relevant environmental variables from WorldClim at 30 arc seconds scale, to have a broad characterization of the variable climatic conditions of both regions, and a climatic envelope for each species. We estimated relative DNA content index and relative monoploid genome values, by flow cytometry, of four most abundant Larrea species throughout their respective ranges. Then we winnow the bioclimatic dataset down to uncorrelated variables and sampled locales, to analyse the degree of association between both intra- and interspecific relative DNA content and climatic variables that are functionally relevant in arid environments using Pearson correlations, general linear and mixed effects models. Within the genus Larrea, relative DNA content increases with rising temperature and decreases with rising precipitation. At the intraspecific level, all four species show relative DNA content variation across climatic conditions. Larrea is a genus that shows genome size variation correlated with climate. Our results are also consistent with the hypothesis that extreme environmental pressures may have facilitated repeated whole genome duplication events in North America, while in South America, reticulate evolution, as allopolyploidization, and speciation might have been climate-dependent since the Oligocene.Fil: Vidal Russell, Romina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Tadey, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Urfusová, Romana. Charles University; República ChecaFil: Urfus, Tomáš. Charles University; República ChecaFil: Souto, Cintia Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentin

Sources of Variation in Hieracium pilosella L.

Department of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Sources of Variation in Hieracium pilosella L.

Department of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Figure 1 in Peaceful revolution in genome size: polyploidy in the Nabidae (Heteroptera); autosomes and nuclear DNA content doubling

Figure 1. Chromosomes of Nabidae species studied, stained with Giemsa (A, D, F, G, M) or with an 18S ribosomal DNA (rDNA) probe (red) applied via fluorescence in situ hybrization (FISH) (B, C, E, H–L, N–P). A, B, Nabis punctatus ♀ 2n = 16 + XX, mitotic metaphase. C, Himacerus apterus ♀ 2n = 36 + XX, mitotic metaphase. D, Nabis rugosus ♂ 2n = 16 + XY + 1 metaphase I, specimen with an additional chromosome (arrow). E, Nabis maoricus ♀ 2n = 18 + XX, mitotic metaphase. F, N. maoricus ♂ 2n = 16 + XY, postpachytene, with sex chromosomes superspiralized. G, H, Nabis biformis ♀ 2n = 16 + XX, mitotic metaphase, with two 18S rDNA signals on each X chromosome. I, Nabis limbatus ♀ 2n = 16 + XX, mitotic metaphase, species with the most distal 18S rDNA signal. J, N. rugosus ♂ 2n = 16 + XY, mitotic metaphase, species with the two 18S rDNA signals on Y chromosome. K, Prostemma guttula ♂ 2n = 26 + XY, metaphase II. L, N. maoricus ♂ 2n = 16 + XY, metaphase II, with Y chromosome showing no 18S rDNA signal. M, N, Prostemma aeneicolle ♀ 2n = 26 + XX, mitotic metaphase. O, H. apterus ♀ 2n = 36 + XXXX, mitotic metaphase, with terminal 18S rDNA signals on four X chromosomes originated by fragmentation. P, N. maoricus ♀ 2n = 18 + XXX, mitotic metaphase, with one X chromosome fragmented outside of the 18S rDNA position. Arrowheads indicate 18S rDNA signal; X and Y are the sex chromosomes. Scale bars: 10 μm.Published as part of <i>Sadílek, David, Vilímová, Jitka & Urfus, Tomáš, 2021, Peaceful revolution in genome size: polyploidy in the Nabidae (Heteroptera); autosomes and nuclear DNA content doubling, pp. 145-157 in Zoological Journal of the Linnean Society 193 (1)</i> on page 149, DOI: 10.1093/zoolinnean/zlaa138, <a href="http://zenodo.org/record/10114866">http://zenodo.org/record/10114866</a&gt

Figure 3. Example relative fluorescence histograms for samples stained with propidium iodide. The 2C in Peaceful revolution in genome size: polyploidy in the Nabidae (Heteroptera); autosomes and nuclear DNA content doubling

Figure 3. Example relative fluorescence histograms for samples stained with propidium iodide. The 2C peaks represent diploid cells, and 4C peaks represent cells in the G2 phase of the cell cycle, with replicated DNA. Standard used: Solanum pseudocapsicum 2C = 2.61 pg. A, Himacerus apterus female with 2n = 36 + XX and 2C = 9.71 pg. B, Nabis maoricus female with 2n = 16 + XX and 2C = 4.21 pg.Published as part of <i>Sadílek, David, Vilímová, Jitka & Urfus, Tomáš, 2021, Peaceful revolution in genome size: polyploidy in the Nabidae (Heteroptera); autosomes and nuclear DNA content doubling, pp. 145-157 in Zoological Journal of the Linnean Society 193 (1)</i> on page 152, DOI: 10.1093/zoolinnean/zlaa138, <a href="http://zenodo.org/record/10114866">http://zenodo.org/record/10114866</a&gt

Polyploid evolution: The ultimate way to grasp the nettle.

Polyploidy is one of the major forces of plant evolution and widespread mixed-ploidy species offer an opportunity to evaluate its significance. We therefore selected the cosmopolitan species Urtica dioica (stinging nettle), examined its cytogeography and pattern of absolute genome size, and assessed correlations with bioclimatic and ecogeographic data (latitude, longitude, elevation). We evaluated variation in ploidy level using an extensive dataset of 7012 samples from 1317 populations covering most of the species' distribution area. The widespread tetraploid cytotype (87%) was strongly prevalent over diploids (13%). A subsequent analysis of absolute genome size proved a uniform Cx-value of core U. dioica (except for U. d. subsp. cypria) whereas other closely related species, namely U. bianorii, U. kioviensis and U. simensis, differed significantly. We detected a positive correlation between relative genome size and longitude and latitude in the complete dataset of European populations and a positive correlation between relative genome size and longitude in a reduced dataset of diploid accessions (the complete dataset of diploids excluding U. d. subsp. kurdistanica). In addition, our data indicate an affinity of most diploids to natural and near-natural habitats and that the tetraploid cytotype and a small part of diploids (population from the Po river basin in northern Italy) tend to inhabit synanthropic sites. To sum up, the pattern of ploidy variation revealed by our study is in many aspects unique to the stinging nettle, being most likely first of all driven by the greater ecological plasticity and invasiveness of the tetraploid cytotype

A pentaploid endosperm and a Penaea-type embryo sac are likely synapomorphies of Azorella (Apiaceae, Azorelloideae)

About 80% of angiosperms form a monosporic Polygonum-type embryo sac, whereas in the remaining species, eleven other types of embryo sac are found. Evidence as to the type of embryo sac is lacking for many plant species, and the role of higher-ploidy endosperm is unknown. In contrast to the rest of the Apiaceae, where a Polygonum-type embryo sac (3n endosperm) has been reported, the few species of the Azorelloideae studied to form a Drusa-type embryo sac (3n endosperm) or a Penaea-type embryo sac (5n endosperm). This variation within Azorelloideae makes this subfamily, and its genus Azorella in particular, a good candidate for studying the evolutionary importance of the embryo sac and endosperm in diversification. We studied the variation in the type of embryo sac and the ploidy level of the endosperm in Andean-Patagonian Azorella and closely related Pozoa on a sample of 101 individuals from 31 populations of 21 species. We employed flow cytometric seed screening and calibrated the results of ploidy level estimation against embryological observations. In addition, we examined the genome size variation of the species sampled. All species of Azorella formed Penaea-type embryo sacs and a pentaploid endosperm, whereas one species of Pozoa formed triploid and the other tetraploid endosperms. Variations in the type of embryo sac and endosperm ploidy have probably shaped the evolution of the different lineages of Azorelloideae in the southern Andes. A Penaea-type embryo sac, which represents a likely synapomorphy of Azorella, is a feature of underestimated significance in the evolution of angiosperms.Fil: Ptáček, Jan. Charles University; República ChecaFil: Sklenář, Petr. Charles University; República ChecaFil: Pinc, Jan. Charles University; República ChecaFil: Urfusová, Romana. Charles University; República ChecaFil: Calviño, Carolina Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Urfus, Tomáš. Charles University; República Chec

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

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