Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Peterson, Angela  (12)
Type of Medium
Language
Year
  • 1
    Language: English
    In: Molecular Phylogenetics and Evolution, 2006, Vol.41(3), pp.579-593
    Description: Molecular studies of 21 species of the large Cactaceae genus representing a variety of intrageneric taxonomic levels revealed a high degree of intra-individual polymorphism of the internal transcribed spacer region (ITS1, 5.8S rDNA, ITS2). Only a few of these ITS copies belong to apparently functional genes, whereas most are probably non-functional (pseudogenes). As a multiple gene family, the ITS region is subjected to concerted evolution. However, the high degree of intra-individual polymorphism of up to 36% in ITS1 and up to 35% in ITS2 suggests a non-concerted evolution of these loci in . Conserved angiosperm motifs of ITS1 and ITS2 were compared between genomic and cDNA ITS clones of . Some of these motifs (e.g., ITS1 motif 1, ‘TGGT’ within ITS2) in combination with the determination of GC-content, length comparisons of the spacers and ITS2 secondary structure (helices II and III) are helpful in the identification of pseudogene rDNA regions.
    Keywords: Internal Transcribed Spacer ; Non-Concerted Evolution ; Mammillaria ; Pseudogene ; Its Motifs ; Its2 Secondary Structure ; Biology
    ISSN: 1055-7903
    E-ISSN: 1095-9513
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Plant Systematics and Evolution, 2013, Vol.299(2), pp.413-438
    Description: The genus Gagea Salisb. is the largest amongst Liliaceae, including 50–300 species. This genus can be subdivided into at least 14 sections: among them, there is the species-rich, relatively late-branching monophyletic sect. Didymobulbos . Most of species and putative hybrids within this section were included in this study for a total of about 148 accessions (corresponding to 35 taxa), almost all collected across the Euro-Mediterranean area. Thirty-seven morpho-anatomical and ontogenetic characters were considered, together with the cpDNA ( trn L– trn F IGS, psb A– trn H IGS) and nrDNA (ITS region) molecular markers. Bayesian analysis revealed the phylogenetic relationships among Didymobulbos taxa, allowing us to demonstrate new circumscriptions of critical species complexes, such as those of G. chrysantha Schult. & Schult.f., G. dubia A. Terracc. and G. granatellii (Parl.) Parl. Also the prominent role played in this section by reticulate evolution is further highlighted: many taxa, often unexpectedly, are inferred to represent hybrids (31 % of investigated taxa). The division into series cannot be maintained as we found extensive molecular evidence of hybridization between them. A new taxonomic setting for Gagea sect. Didymobulbos is proposed, and five new species are described.
    Keywords: Gagea ; Liliaceae ; ITS ; Karyology ; Networks ; Phylogeny ; Taxonomy ; L–F IGS ; A–H IGS
    ISSN: 0378-2697
    E-ISSN: 1615-6110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Organisms Diversity & Evolution, 2011, Vol.11(5), pp.387-407
    Description: A new region of speciation for the genus Gagea (Liliaceae) was investigated (Bogda-Shan and Urumqi; northwestern Xinjiang, China). Two species were recorded as new for the region ( G. rufidula , G. davlianidzeae ); three species are described as new to science ( G. angelae, G. jensii and G. huochengensis ). The description of G. nigra is emendated. Sequence data (cpDNA: trn L- trn F IGS+ psb A- trn H IGS, nrDNA: ITS), including representatives of all Gagea sections, were used to compare the new species with closely related taxa. A nuclear single copy gene region (pCOS At 103) was analysed for representatives of the Sects. Minimae and Gagea . Network analysis of cpDNA and nDNA indicates hybridization and recent speciation in Xinjiang. ITS and pCOS At 103 sequences reveal gene flow between G. davlianidzeae and G. nigra . A cpDNA haplotype network constructed from representatives of Sect. Gagea was highly informative phylogenetically. Gagea angelae and G . huochengensis , sharing gene flow, are related closely to a basal clade represented by G. ancestralis , G. xiphoidea and G. capusii , which may include the putative progenitor of all other taxa of the large Eurasian Sect. Gagea . Whereas speciation in Sect. Minimae seems to be driven mainly by hybridization, speciation in the Sect. Gagea may be influenced by both hybridization and geographical separation. We confirm the monophyly of Sects. Bulbiferae and Minimae .
    Keywords: cpDNA ; Gagea ; hybridization ; ITS ; Liliales ; At ; speciation
    ISSN: 1439-6092
    E-ISSN: 1618-1077
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: International Journal of Plant Sciences October 2007, Vol.168(8), pp.1157-1160
    Description: The increasing number of pseudogenic internal transcribed spacer (ITS) regions (ITS1, 5.8S rDNA, ITS2) reported for plant taxa raises questions—for example, concerning the proportion of functional copies. Our application of quantitative PCR (qPCR) with genomic DNA under stringent conditions revealed that 〈3% of the copies of the ITS region were putatively functional in the genomic PCR pool in Mammillaria . The selective amplification of functional copies of the ITS region was possible through the utilization of conserved angiosperm motifs (ITS1 motif and 5.8S motif) as primer annealing sites. Our study displays that it is possible to quantify the proportion of functional copies of repetitive DNA regions through their selective amplification by qPCR.
    Keywords: Polymerase Chain Reaction -- Genetic Aspects ; Genomic Libraries -- Evaluation ; Angiosperms -- Genetic Aspects ; Genetic Polymorphisms -- Evaluation;
    ISSN: 10585893
    E-ISSN: 15375315
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    In: Nordic Journal of Botany, December 2011, Vol.29(6), pp.722-733
    Description: The typification of the name Evers (a lectotype in GZU is designated here) and studies of living topotype material, led us to conclude that is a full synonym of , sharing morphological, karyological (2n=84) and molecular (ITS region, L–F IGS, A–nH IGS) features with the latter species. , as newly circumscribed here, shows a close relationship with (M. Bieb.) Sweet and, above all, with K. Koch (possibly a hybridogenous taxon). In short, our new morphological and molecular data provide new evidence for hybridization and introgression between the closely related and (both in sect. s).
    Keywords: Botany;
    ISSN: 0107-055X
    E-ISSN: 1756-1051
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Canadian Journal of Botany, March, 2008, Vol.86(3), p.300(6)
    Keywords: Phylogeny -- Research ; Pseudogenes -- Identification And Classification ; Plant Genetics -- Research
    ISSN: 0008-4026
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Journal of Plant Research, 2008, Vol.121(3), pp.261-270
    Description: The internal transcribed spacer (ITS) region (ITS1, 5.8S rDNA, ITS2) represents the most widely applied nuclear marker in eukaryotic phylogenetics. Although this region has been assumed to evolve in concert, the number of investigations revealing high degrees of intra-individual polymorphism connected with the presence of pseudogenes has risen. The 5.8S rDNA is the most important diagnostic marker for functionality of the ITS region. In Mammillaria , intra-individual 5.8S rDNA polymorphisms of up to 36% and up to nine different types have been found. Twenty-eight of 30 cloned genomic Mammillaria sequences were identified as putative pseudogenes. For the identification of pseudogenic ITS regions, in addition to formal tests based on substitution rates, we attempted to focus on functional features of the 5.8S rDNA (5.8S motif, secondary structure). The importance of functional data for the identification of pseudogenes is outlined and discussed. The identification of pseudogenes is essential, because they may cause erroneous phylogenies and taxonomic problems.
    Keywords: 5.8S rDNA ; Intra-individual variability ; Mammillaria ; Pseudogene ; Secondary structure
    ISSN: 0918-9440
    E-ISSN: 1618-0860
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Plant Systematics and Evolution, 2016, Vol.302(8), pp.985-1007
    Description: The most important center of speciation in the genus Gagea is thought to be in Central Asia. Here, we focus on species diversity in southeastern Kazakhstan (around Almaty, Ili-Alatau range of the Western Tian-Shan mountains). We studied an elevational transect, reaching from lowland steppes to the alpine zone (500–2750 m a. s. l.), and carried out detailed morphological and molecular investigations for populations of Gagea spp. Nine species were identified in different altitudinal zones; one of these ( Gagea almaatensis ) is described as new to science. We could detect two altitudinal contact zones between closely related species: G . filiformis and G. granulosa (sect. Minima e), and G . almaatensis and G. kuraminica (sect. Gagea ). Morphological and molecular investigations (ITS data and cpDNA networks) indicate ongoing hybridization of co-occurring G. filiformis into G. granulosa and putative bidirectional hybridization events between G. almaatensis and G. kuraminica.
    Keywords: cpDNA ; Gagea ; Hybridization ; ITS ; Phylogeny ; Taxonomy
    ISSN: 0378-2697
    E-ISSN: 2199-6881
    E-ISSN: 16156110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Botany (Botanique), 2008, Vol.86(3), pp.300-305
    Description: The internal transcribed spacer (ITS) region (ITS1, 5.8S rDNA, ITS2) represents one of the most popular molecular markers in phylogenetics. The number of investigations revealing high degrees of intra-individual polymorphism connected with the presence of pseudogenic ITS regions is on the increase. Studies including pseudogenic ITS regions can lead to erroneous phylogenetic trees and false taxonomic conclusions. For their recognition, we focus on the 5.8S rDNA as the functional part of this region, which is also affected by degeneration processes. We outline three conserved Viridiplantae 5.8S motifs: GAATTGCAGAAwyC, TTTGAAyGCA, CGATGAAGAACGyAGC, which can be simply checked in sequence alignments. The latter 5.8S motif we also recognised in the large subunit RNA (LSU) of Escherichia coli . The utility of different methods for pseudogene detection based on easily recognisable 5.8S sequence motifs by comparison with 5.8S secondary structure reconstructions and statistical tests are discussed and illustrated with three previously published angiosperm data sets.
    Description: La rgion (ITS) de lespaceur interne transcrite (ITS1, 5.8S rADN, ITS2) reprsente un des marqueurs des plus populaires en phylognie. On observe une augmentation du nombre de recherches montrant une prsence importante accrue de polymorphisme intra individuel, relie avec la prsence de rgions ITS pseudognes. Les tudes incluant des rgions ITS pseudognes peuvent conduire des arbres phylogntiques errons et de fausses conclusions taxonomiques. Afin de les reconnatre, les auteurs se concentrent sur le 5.8S rADN comme partie fonctionnelle de cette rgion, laquelle est galement affecte par le processus de dgnrescence. Ils soulignent trois motifs 5.8S Viridiplantae: GAATTGCAGAAwyC, TTTGAAyGCA, CGATGAAGAACGyAGC, quon peut simplement vrifier en alignements de squences. Ils reconnaissent galement le dernier motif 5.8S dans la grande sous-unit ARN (LSU) chez l Escheria coli . On discute lutilit de diffrentes mthodes pour dtecter les pseudognes, bases sur des motifs de squences facilement reconnaissables du 5.8S, comparativement aux reconstructions secondaires et aux tests statistiques trois ensembles de donnes provenant dangiospermes et pralablement publies, servent illustrer ce propos.
    Keywords: 5.8s Rdna ; Motif ; Pseudogene ; Internal Transcribed Spacer Region ; 5.8 Radn ; Motif ; Pseudogne ; Rgion De Lespaceur Interne Transcrite
    ISSN: 1916-2790
    E-ISSN: 1916-2804
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    In: Ecology and Evolution, May 2019, Vol.9(10), pp.5870-5890
    Description: The Irano‐Turanian (IT) floristic region is considered an important center of origin for many taxa. However, there is a lack of studies dealing with typical IT genera that also occur in neighboring areas. The species‐rich monocot genus Salisb. shows a center of diversity in IT region and a distribution in adjacent regions, therefore representing a good study object to investigate spatial and temporal relationships among IT region and its neighboring areas (East Asia, Euro‐Siberia, Himalaya, and Mediterranean). We aimed at (a) testing the origin of the genus and of its major lineages in the IT region, (b) reconstructing divergence times, and (c) reconstructing colonization events. To address these problems, sequences of the ribosomal DNA internal transcribed spacer (ITS) region of 418 individuals and chloroplast intergenic spacers sequences (A‐H, L‐F) of 497 individuals, representing 116 species from all sections of the genus and nearly its entire distribution area were analyzed. Divergence times were estimated under a random molecular clock based on nrITS phylogeny, which was the most complete data set regarding the representation of species and distribution areas. Ancestral distribution ranges were estimated for the nrITS data set as well as for a combined data set, revealing that most likely originated in southwestern Asia. This genus first diversified there starting in the Early Miocene. In the Middle Miocene, migrated to the Mediterranean and to East Asia, while migration into Euro‐Siberia took place in the Late Miocene. During the Pleistocene, the Arctic was colonized and the most widespread species, reached North America. The Mediterranean basin was colonized multiple times from southwestern Asia or Euro‐Siberia. Most of the currently existing species originated during the last 3 Ma. Divergence time estimation and ancestral range reconstructions were carried out for the species‐rich monocot genus (Liliaceae). Our study could demonstrate that the species‐rich Irano‐Turanian (IT) floristic region, a current centre of species diversity, is also the origin of the genus and of its major linages. Colonisation of adjacent areas started from the IT floristic region and benefit from periods of climatic changes creating dry habits. Therefore, our study supports that the IT region is an important source of taxa for adjacent areas of Euro‐Siberia.
    Keywords: Ancestral Area Reconstruction ; Biogeography ; Dated Phylogeny ; Gagea ; Irano‐Turanian Region ; Southwestern Asia
    ISSN: 2045-7758
    E-ISSN: 2045-7758
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages