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Brandon T. Sinn - One of the best experts on this subject based on the ideXlab platform.
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total duplication of the small single copy region in the angiosperm plastome rearrangement and inverted repeat instability in Asarum
American Journal of Botany, 2018Co-Authors: Lawrence M. Kelly, Brandon T. Sinn, Dylan D Sedmak, John V FreudensteinAbstract:PREMISE OF THE STUDY As more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes). METHODS Illumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum. Sequenced plastomes were compared in a phylogenetic context provided by maximum likelihood and parsimony inferences made using an additional 18 publicly available plastomes from early-diverging angiosperm lineages. KEY RESULTS In contrast to previously published magnoliid plastomes and the newly sequenced Saruma henryi plastome published here, Asarum plastomes have undergone extensive disruption and contain extremely lengthy AT-repeat regions. The entirety of the small single copy region (SSC) of A. canadense and A. sieboldii var. sieboldii has been incorporated into the inverted repeat regions (IR), and the SSC of A. delavayi is only 14 bp long. All sampled Asarum plastomes share an inversion of a large portion of the large single copy region (LSC) such that trnE-UUC is adjacent to the LSC-IR boundary. CONCLUSIONS Plastome divergence in Asarum appears to be consistent with trends seen in highly rearranged plastomes of the monocots and eudicots. We propose that plastome instability in Asarum is due to repetitive motifs that serve as recombinatory substrates and reduce genome stability.
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Asarum rosei (Aristolochiaceae), a new species from the Blue Ridge Escarpment of North Carolina, USA
Phytotaxa, 2017Co-Authors: Brandon T. SinnAbstract:Hundreds of years of botanical exploration in heavily populated and highly accessible eastern North America have not exhausted taxonomic prospects in the region. Here, I describe a new species of Asarum (Aristolochiaceae), Asarum rosei B.T.Sinn, from North Carolina, USA. This species is characterized and contrasted with species in Asarum subgenus Heterotropa section Hexastylis , and a revised artificial taxonomic key to the similar species in the section is provided.
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Asarum chueyi aristolochiaceae a new species from the foothills of the blue ridge mountains of tennessee and virginia usa
Phytotaxa, 2015Co-Authors: Brandon T. SinnAbstract:The forests of eastern North America continue to yield new species, despite more than 200 years of botanical exploration. As a result of fieldwork conducted from 2012–2014, a new Asarum (Aristolochiaceae) species was found in the foothills of the Blue Ridge Mountains of Tennessee and Virginia. This species, A. chueyi , is here distinguished from other North American Asarum species by a unique combination of several morphological characters (calyx tube shape, style extension length, abaxial sepal reticulation, and stamen morphology). Furthermore, a taxonomic key to the species of Blomquist’s informal Virginica group, along with a new combination for Hexastylis sorriei Gaddy, which has not been validly published in Asarum , is provided.
Lawrence M. Kelly - One of the best experts on this subject based on the ideXlab platform.
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total duplication of the small single copy region in the angiosperm plastome rearrangement and inverted repeat instability in Asarum
American Journal of Botany, 2018Co-Authors: Lawrence M. Kelly, Brandon T. Sinn, Dylan D Sedmak, John V FreudensteinAbstract:PREMISE OF THE STUDY As more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes). METHODS Illumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum. Sequenced plastomes were compared in a phylogenetic context provided by maximum likelihood and parsimony inferences made using an additional 18 publicly available plastomes from early-diverging angiosperm lineages. KEY RESULTS In contrast to previously published magnoliid plastomes and the newly sequenced Saruma henryi plastome published here, Asarum plastomes have undergone extensive disruption and contain extremely lengthy AT-repeat regions. The entirety of the small single copy region (SSC) of A. canadense and A. sieboldii var. sieboldii has been incorporated into the inverted repeat regions (IR), and the SSC of A. delavayi is only 14 bp long. All sampled Asarum plastomes share an inversion of a large portion of the large single copy region (LSC) such that trnE-UUC is adjacent to the LSC-IR boundary. CONCLUSIONS Plastome divergence in Asarum appears to be consistent with trends seen in highly rearranged plastomes of the monocots and eudicots. We propose that plastome instability in Asarum is due to repetitive motifs that serve as recombinatory substrates and reduce genome stability.
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Taxonomy of Asarum Section Asarum (Aristolochiaceae)
Systematic Botany, 2009Co-Authors: Lawrence M. KellyAbstract:Abstract Asarum sect. Asarum is a monophyletic group of 14 species distributed through North America, Europe, and Asia. The section is here treated in a taxonomic monograph based on morphological study of field-collected material and herbarium specimens. A key, descriptions, distribution maps, and citations of representative specimens are provided, and available information is reviewed on the pollination biology and phylogenetic relationships within the group. Six species of sect. Asarum are recognized in North America: A. canadense is widespread in the east, and the others range from widespread to narrow endemics in the west. Asarum canadense, which has at times been divided into several species or infraspecific taxa, is here recognized as a single species based on a lack of reliable differences among the variants. Asarum europaeum, which is the most widespread species in the section, has been similarly split historically, but also is treated here as a single taxon. In Asia, section Asarum consists of se...
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Phylogenetic relationships in Asarum (Aristolochiaceae) based on morphology and ITS sequences
American journal of botany, 1998Co-Authors: Lawrence M. KellyAbstract:A cladistic analysis of Asarum was conducted using data from morphology and nuclear ribosomal internal transcribed spacer sequences (ITS) to examine the relationships among several groups of taxa that have often been treated as segregate genera. Morphological and molecular data were analyzed simultaneously for a set of 36 terminals representing the taxonomic, morphological, and geographic diversity of the genus. The two data sources are generally congruent and together provide more resolution than either by itself. The data support two main clades in the genus: an Asarum sensu stricto clade and an AsiAsarum + Hexastylis + Heterotropa clade. The former consists of - 17 species and is distributed through North America, Europe, and Asia. Within this group, the North American species are monophyletic and derived from within the paraphyletic Asiatic species group. The AsiAsarum + Hexastylis + Heterotropa clade consists of two Asiatic segregates and the North American segregate, Hexastylis. Resolution within this group supports both the monophyly of Heterotropa and a sister group relationship of AsiAsarum to Hexastylis + Heterotropa. Hexastylis is paraphyletic and occurs as two separate clades on the tree; one of these is sister to Heterotropa and the other is sister to the latter plus Heterotropa. The phylogenetic data provide several clues about the biogeographic history of Asarum and suggest that: (1) the genus likely originated in Asia and underwent substantial diversification prior to colonizing North America; and (2) Asarum in North America represents at least two historically distinct groups that likely achieved their North American distributions at different times. The results of these analyses support recognition of two subgenera, Asarum and Heterotropa, each with two sections: Asarum and Geotaenium of the former, and AsiAsarum and Heterotropa of the latter. Asarum sect. CeratAsarum (Hexastylis) is here treated as a synonym of Asarum sect. Heterotropa. A taxonomic conspectus of the genus is provided, and the combination Asarum sect. Geotaenium (F Maek.) L. Kelly is made in accordance with the revised circumscription of taxa.
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A cladistic analysis of Asarum (Aristolochiaceae) and implications for the evolution of herkogamy.
American journal of botany, 1997Co-Authors: Lawrence M. KellyAbstract:A cladistic analysis of Asarum was conducted to examine relationships among species within the genus and to test the monophyly of several groups of taxa that have often been treated as segregate genera. Thirty-two species were drawn from throughout the range of the genus, representing a broad sample of sections and all segregate genera. The data matrix included 37 characters derived from various aspects of vegetative and floral morphology. A strict consensus of all most parsimonious trees suggests that Asarum s.l. is monophyletic and consists of two main clades: an Asarum clade, which is characterized by connate styles and inferior ovaries, and an AsiAsarum-Hexastylis-Heterotropa clade, which is characterized by ridges on the inner perianth surface, dorsal stigmas, and bifid style extensions. The latter is a large and morphologically diverse clade that includes the North American segregate Hexastylis and two Asiatic segregates. Examination of pollination mechanisms in the context of this phylogeny supports the conclusion that herkogamy, and thus obligate insect pollination, is derived from a plesiomorphic condition of autonomous self-pollination. Associated with herkogamy are characters such as glandular trichomes and other ornamentation of the surface of the calyx that probably represent increased specialization to attract insect pollinators. This study also indicates that chromosomal evolution has occurred via aneuploid decrease from an ancestral chromosome number of 2n = 26 to 2n = 24 in Heterotropa. The recognition of two subgenera, subgenus Asarum and subgenus Heterotropa, corresponding to the two clades in the cladistic analysis, is recommended.
John V Freudenstein - One of the best experts on this subject based on the ideXlab platform.
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total duplication of the small single copy region in the angiosperm plastome rearrangement and inverted repeat instability in Asarum
American Journal of Botany, 2018Co-Authors: Lawrence M. Kelly, Brandon T. Sinn, Dylan D Sedmak, John V FreudensteinAbstract:PREMISE OF THE STUDY As more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes). METHODS Illumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum. Sequenced plastomes were compared in a phylogenetic context provided by maximum likelihood and parsimony inferences made using an additional 18 publicly available plastomes from early-diverging angiosperm lineages. KEY RESULTS In contrast to previously published magnoliid plastomes and the newly sequenced Saruma henryi plastome published here, Asarum plastomes have undergone extensive disruption and contain extremely lengthy AT-repeat regions. The entirety of the small single copy region (SSC) of A. canadense and A. sieboldii var. sieboldii has been incorporated into the inverted repeat regions (IR), and the SSC of A. delavayi is only 14 bp long. All sampled Asarum plastomes share an inversion of a large portion of the large single copy region (LSC) such that trnE-UUC is adjacent to the LSC-IR boundary. CONCLUSIONS Plastome divergence in Asarum appears to be consistent with trends seen in highly rearranged plastomes of the monocots and eudicots. We propose that plastome instability in Asarum is due to repetitive motifs that serve as recombinatory substrates and reduce genome stability.
Dylan D Sedmak - One of the best experts on this subject based on the ideXlab platform.
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total duplication of the small single copy region in the angiosperm plastome rearrangement and inverted repeat instability in Asarum
American Journal of Botany, 2018Co-Authors: Lawrence M. Kelly, Brandon T. Sinn, Dylan D Sedmak, John V FreudensteinAbstract:PREMISE OF THE STUDY As more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes). METHODS Illumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum. Sequenced plastomes were compared in a phylogenetic context provided by maximum likelihood and parsimony inferences made using an additional 18 publicly available plastomes from early-diverging angiosperm lineages. KEY RESULTS In contrast to previously published magnoliid plastomes and the newly sequenced Saruma henryi plastome published here, Asarum plastomes have undergone extensive disruption and contain extremely lengthy AT-repeat regions. The entirety of the small single copy region (SSC) of A. canadense and A. sieboldii var. sieboldii has been incorporated into the inverted repeat regions (IR), and the SSC of A. delavayi is only 14 bp long. All sampled Asarum plastomes share an inversion of a large portion of the large single copy region (LSC) such that trnE-UUC is adjacent to the LSC-IR boundary. CONCLUSIONS Plastome divergence in Asarum appears to be consistent with trends seen in highly rearranged plastomes of the monocots and eudicots. We propose that plastome instability in Asarum is due to repetitive motifs that serve as recombinatory substrates and reduce genome stability.
Gong Fan - One of the best experts on this subject based on the ideXlab platform.
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chemical characterization of essential oil in rhizoma Asarum from different sources using gc ms with resolution improved by data processing techniques
Flavour and Fragrance Journal, 2006Co-Authors: Gong Fan, Wang Botang, Chau FootimAbstract:Rhizoma Asarum has been widely used both in phytotherapy and in the food industry because of its pharmacological activities and odoriferous properties. However, besides desirable pharmacological effects, Asarum oil is also found to exhibit toxic effects. In this study, gas chromatography–mass spectrometry (GC-MS) with resolution improved by data processing techniques in chemometrics was investigated as a method to chemically characterize essential oils of raw materials of Rhizoma Asarum from Liaoning, Gansu and Hunan in China. With the help of chemometric approaches on two-dimensional data from GC-MS, the separation ability of GC was mathematically improved and many more chemical components could be separated and identified since overlapping peak clusters could be resolved into pure chromatograms and related mass spectra for each of the components involved. Qualitative and quantitative determination was conducted with the pure chromatograms and mass spectra obtained by use of similarity searches in the MS databases and the overall volume integration technique, respectively. Moreover, the information on retention times was also used for the identification. The results showed that 96, 94 and 93 chemical components were separated; 69, 67 and 66 of them were tentatively identified, which accounted for about 97.68, 97.51 and 97.63% of the total relative content of the essential oils of Rhizoma Asarum from Liaoning, Gansu and Hunan, respectively. In comparison with the determined constituents in essential oils of Rhizoma Asarum from three producing sources, most of them matched each other. Copyright © 2006 John Wiley & Sons, Ltd.
