• MeSH
• Ginkgo biloba genetika   MeSH
• polyploidie * MeSH
• Publikační typ
• dopisy MeSH
• práce podpořená grantem MeSH

The past decade has witnessed a tremendous increase in interest in polyploidy, which may partly be related to the development of new powerful genetic and genomic tools. These have provided numerous insights into mainly genetic and genomic consequences of polyploidy, dramatically improving our understanding of the dynamics of the polyploidization process and its importance as a mechanism in animal evolution. In contrast, several other aspects of polyploidization, such as physiology, ecology and development, have received considerably less attention. Our aim is not to make an exhaustive review of current knowledge about animal polyploidy, but rather to thoroughly elaborate on some very fundamental questions which still remain open or even neglected. In particular, we show that properties of new polyploid lineages largely depend upon the proximate way in which they arose, but the evolutionary pathways to polyploidy are often unresolved. To help researchers orientate amongst the number of pathways to polyploidy, we provide an extensive review of particular scenarios proposed in distinct animal taxa. We discuss how polyploidy relates to hybridization, particularly with respect to asexuality, and elaborate on whether clonal triploids may help to overcome the constraints of aneuploidy, thereby serving as a triploid bridge towards the establishment of new polyploid species. We further show that in most animal asexual complexes clonal lineages may become established only under one ploidy level (usually either di- or triploidy), and that it is rather rare to see the coexistence of successful clones of different ploidies. We discuss why the rate of polyploidization is higher in some taxa than in others, and what tools we have to evaluate the rate of polyploidization. Finally, we review some of the immediate physiological and developmental effects of polyploidy which are related to the genome size/cell size relation and show how studies of polyploidy may enhance the study of macroecology and developmental biology. See also the sister article focusing on plants by Weiss-Schneeweiss et al. in this themed issue.

• MeSH
• aneuploidie MeSH
• délka genomu MeSH
• diploidie MeSH
• ekosystém MeSH
• fenotyp MeSH
• fylogeneze MeSH
• hybridizace genetická MeSH
• molekulární evoluce * MeSH
• polyploidie * MeSH
• velikost buněčného jádra MeSH
• velikost buňky MeSH
• vznik druhů (genetika) MeSH
• žáby klasifikace   genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Because most clonal vertebrates have hybrid genomic constitutions, tight linkages are assumed among hybridization, clonality, and polyploidy. However, predictions about how these processes mechanistically relate during the switch from sexual to clonal reproduction have not been validated. Therefore, we performed a crossing experiment to test the hypothesis that interspecific hybridization per se initiated clonal diploid and triploid spined loaches (Cobitis) and their gynogenetic reproduction. We reared two F1 families resulting from the crossing of 14 pairs of two sexual species, and found their diploid hybrid constitution and a 1:1 sex ratio. While males were infertile, females produced unreduced nonrecombinant eggs (100%). Synthetic triploid females and males (96.3%) resulted in each of nine backcrossed families from eggs of synthesized diploid F1s fertilized by haploid sperm from sexual males. Five individuals (3.7%) from one backcross family were genetically identical to the somatic cells of the mother and originated via gynogenesis; the sperm of the sexual male only triggered clonal development of the egg. Our reconstruction of the evolutionary route from sexuality to clonality and polyploidy in these fish shows that clonality and gynogenesis may have been directly triggered by interspecific hybridization and that polyploidy is a consequence, not a cause, of clonality.

• MeSH
• biologická evoluce MeSH
• hybridizace genetická MeSH
• máloostní genetika   MeSH
• molekulární sekvence - údaje MeSH
• nepohlavní rozmnožování MeSH
• polymerázová řetězová reakce MeSH
• polyploidie MeSH
• rozmnožování MeSH
• rybí proteiny genetika   MeSH
• sekvenční analýza DNA MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Německo MeSH
• Slovinsko MeSH

• MeSH
• Arabidopsis genetika   MeSH
• chromozomy rostlin genetika   MeSH
• cytogenetické vyšetření metody   MeSH
• genomika metody   MeSH
• polyploidie * MeSH
• Publikační typ
• úvodní články MeSH

This article describes the use of cytogenomic and molecular approaches to explore the origin and evolution of Cardamine schulzii, a textbook example of a recent allopolyploid, in its ~110-year history of human-induced hybridization and allopolyploidy in the Swiss Alps. Triploids are typically viewed as bridges between diploids and tetraploids but rarely as parental genomes of high-level hybrids and polyploids. The genome of the triploid semifertile hybrid Cardamine × insueta (2n = 24, RRA) was shown to combine the parental genomes of two diploid (2n = 2x = 16) species, Cardamine amara (AA) and Cardamine rivularis (RR). These parental genomes have remained structurally stable within the triploid genome over the >100 years since its origin. Furthermore, we provide compelling evidence that the alleged recent polyploid C. schulzii is not an autohexaploid derivative of C. × insueta. Instead, at least two hybridization events involving C. × insueta and the hypotetraploid Cardamine pratensis (PPPP, 2n = 4x-2 = 30) have resulted in the origin of the trigenomic hypopentaploid (2n = 5x-2 = 38, PPRRA) and hypohexaploid (2n = 6x-2 = 46, PPPPRA). These data show that the semifertile triploid hybrid can promote a merger of three different genomes and demonstrate how important it is to reexamine the routinely repeated textbook examples using modern techniques.

• MeSH
• biologická evoluce * MeSH
• Cardamine genetika   MeSH
• druhová specificita MeSH
• fylogeneze MeSH
• genom rostlinný genetika   MeSH
• genová dávka MeSH
• hybridizace genetická MeSH
• hybridizace in situ MeSH
• molekulární sekvence - údaje MeSH
• nestabilita genomu * MeSH
• polyploidie MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• triploidie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND AND AIMS: Speciation in angiosperms can be accompanied by changes in floral colour that may influence pollinator preference and reproductive isolation. This study investigates whether changes in floral colour can accompany polyploid and homoploid hybridization, important processes in angiosperm evolution. METHODS: Spectral reflectance of corolla tissue was examined for 60 Nicotiana (Solanaceae) accessions (41 taxa) based on spectral shape (corresponding to pigmentation) as well as bee and hummingbird colour perception in order to assess patterns of floral colour evolution. Polyploid and homoploid hybrid spectra were compared with those of their progenitors to evaluate whether hybridization has resulted in floral colour shifts. KEY RESULTS: Floral colour categories in Nicotiana seem to have arisen multiple times independently during the evolution of the genus. Most younger polyploids displayed an unexpected floral colour, considering those of their progenitors, in the colour perception of at least one pollinator type, whereas older polyploids tended to resemble one or both of their progenitors. CONCLUSIONS: Floral colour evolution in Nicotiana is weakly constrained by phylogeny, and colour shifts do occur in association with both polyploid and homoploid hybrid divergence. Transgressive floral colour in N. tabacum has arisen by inheritance of anthocyanin pigmentation from its paternal progenitor while having a plastid phenotype like its maternal progenitor. Potentially, floral colour evolution has been driven by, or resulted in, pollinator shifts. However, those polyploids that are not sympatric (on a regional scale) with their progenitor lineages are typically not divergent in floral colour from them, perhaps because of a lack of competition for pollinators.

• MeSH
• barva * MeSH
• biologická evoluce * MeSH
• hybridizace genetická * MeSH
• květy fyziologie   MeSH
• pigmentace MeSH
• polyploidie * MeSH
• tabák genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite their complex evolutionary histories, aquatic plants are highly underrepresented in contemporary biosystematic studies. Of them, the genus Callitriche is particularly interesting because of such evolutionary features as wide variation in chromosome numbers and pollination systems. However, taxonomic difficulties have prevented broader investigation of this genus. In this study we applied flow cytometry to Callitriche for the first time in order to gain an insight into evolutionary processes and genome size differentiation in the genus. Flow cytometry complemented by confirmation of chromosome counts was applied to an extensive dataset of 1077 Callitriche individuals from 495 localities in 11 European countries and the USA. Genome size was determined for 12 taxa. The results suggest that many important processes have interacted in the evolution of the genus, including polyploidization and hybridization. Incongruence between genome size and ploidy level, intraspecific variation in genome size, formation of autotriploid and hybridization between species with different pollination systems were also detected. Hybridization takes place particularly in the diploid-tetraploid complex C. cophocarpa-C. platycarpa, for which the triploid hybrids were frequently recorded in the area of co-occurrence of its parents. A hitherto unknown hybrid (probably C. hamulata × C. cophocarpa) with a unique chromosome number was discovered in the Czech Republic. However, hybridization occurs very rarely among most of the studied species. The main ecological preferences were also compared among the taxa collected. Although Callitriche taxa often grow in mixed populations, the ecological preferences of individual species are distinctly different in some cases. Anyway, flow cytometry is a very efficient method for taxonomic delimitation, determination and investigation of Callitriche species, and is even able to distinguish homoploid taxa and identify introduced species.

• MeSH
• délka genomu * MeSH
• genom rostlinný genetika   MeSH
• květy genetika   MeSH
• molekulární evoluce * MeSH
• Plantago genetika   MeSH
• polyploidie MeSH
• průtoková cytometrie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

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 Knautia arvensis (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 K. arvensis 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 K. arvensis a unique system for addressing general questions of polyploid research.

• MeSH
• analýza polymorfismu délky amplifikovaných restrikčních fragmentů MeSH
• biologická evoluce * MeSH
• chrysotilový azbest MeSH
• Dipsacaceae genetika   metabolismus   MeSH
• ekosystém MeSH
• fenotyp MeSH
• fylogeneze MeSH
• genom rostlinný MeSH
• haplotypy MeSH
• plastidy genetika   MeSH
• polyploidie * MeSH
• půda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH