1,007 research outputs found

    Notes on genetic variation in Sedum sarmentosum (Crassulaceae): Implications for the origin of southern Korean populations

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    7 p., 1 mapa, tablasThe succulent herbaceous perennial Sedum sarmentosum commonly grows in the southern part of the Korean Peninsula. It is a species native to China, most likely introduced into Korea due to its edible and medicinal uses. If plants were introduced from a single source, we would expect no or low levels of genetic variation in Korean populations. Alternatively, if plants were introduced from multiple sources, we would expect, in contrast, high levels of genetic diversity. To test which is more likely, we surveyed the degree of allozyme variation in ten populations of this species from southern Korea. We found that S. sarmentosum was monomorphic at all fifteen allozyme loci. How- ever, two congeners (S. polytrichoides and S. kamtschaticum) and two related species (Hylotelephium ussuriense and H. verticillatum) maintain moderate to high levels of genetic diversity (H = 0.144, 0.203, 0.201, and 0.204, respec- tively). We suggest that southern Korean populations of S. sarmentosum likely descended from a single introduction of a few plants and then became naturalized exclusively via vegetative spreading (as plants in Korea, but also as occurs in other parts of its native and naturalized range, are sterile).This research was supported by the National Institute of Biological Resources, Republic of Korea to M.G. C. and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2013R1A1A2063524 and NRF-2013R1A1A 3010892 to M.G.C. and M.Y.C., respectively). This research was also supported by the grant no. 201630I024 (“Proyecto Intramural Especial, PIE” from the CSIC, Spain) to J.L.-P.Peer reviewe

    Is the Baekdudaegan “the Southern Appalachians of the East”? A comparison between these mountain systems, focusing on their role as glacial refugia

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    11 p., mapas, tablasBased on genetic studies and palaeoecological surveys, the main Korean mountain range, the so- called “Baekdudaegan” (BDDG), has been recently suggested to be a major glacial refugium at the Last Glacial Maximum (LGM) for the boreal and temperate flora of northeastern Asia. On the basis of its shared role as a glacial refugium, and on a series of striking similarities in floristic richness and orographic features, the BDDG would constitute a sort of “eastern counterpart” of the Southern Appalachians. Given its floristic, biogeo- graphic, and cultural value, the BDDG merits high priority for conservation.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2013R1A1A2063524 and NRF-2013R1A1A3010892 to M.G.C. and M.Y.C., respectivelyPeer reviewe

    Genetic Evidence of a Progenitor-Derivative Species Pair in East Asian "Lilium"

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    8 p., tablas, mapasBoreal Lilium distichum and temperate L. tsingtauense are morphologically very similar, thus they have been placed in the section Martagon. Recent molecular phylogenetic analyses revealed that L. distichum and L. tsingtauense are indeed the most closely related species within that section. Lilium distichum has a wider geographic range and a broader niche than L. tsingtauense. We hypothesized that L. distichum— L. tsingtauense might be a classical “progenitor—derivative” (P–D) species pair and examined the levels of allozyme diversity in the two species in South Korea. Whereas the allelic composition of L. tsingtauense represented a subset of L. distichum, the former had significantly lower allozyme variability at both the population and the species levels than the latter. Except for the locus Fe (fluorescent esterase), allele frequencies of L. distichum were very similar to those of L. tsingtauense. Accordingly, pairwise genetic identities between populations of L. distichum and L. tsingtauense were very high, with a mean of 0.919. Our allozyme results support the hypothesis that L. tsingtauense is a derivative species of the progenitor L. distichum.This research was supported by the Basic Science Program through the National Research Foundation of Korea (NRF-2013R1A1A3010892) funded by the Ministry of Education, Science and Technology, the Republic of Korea to M.Y.C.Peer reviewe

    Population genetic structure of Sedum polytrichoides (Crassulaceae): Insights into barriers to gene flow

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    10 p., tablas, gráf.An area comprising Juwangsan National Park and its adjacent mountains (southeastern Korean Pen- insula) is a good model system for testing the effects of physical barriers to gene flows in plant populations. We predicted that plant species consisting of isolated populations are genetically more differentiated than those that are rather continuously distributed. Most populations of Sedum polytrichoides occur in four isolated valleys, and we assessed the genetic variability and structures using twelve allozyme loci in ten populations. We also com- pared the present results to earlier findings pertaining to the two co-occurring herbs Hylotelephium ussuriense (≡ Sedum ussuriense) (growing only in the four isolated valleys) and S. kamtschaticum (rather continuously dis- tributed). We found moderate levels of within-population genetic variation in S. polytrichoides (H = 0.112). Estimates of among-population divergence in S. polytrichoides were also moderate (F = 0.250) and, as expected, very similar to that of H. ussuriense (0.261) but considerably higher than the variation in S. kamtschat- icum (0.165). An analysis of molecular variance (AMOVA) revealed that S. polytrichoides and H. ussuriense had higher percentages of among-valley variation (19% each) than S. kamtschaticum (4%). Most of this vari- ation, as also indicated by the STRUCTURE program, was due to differences in genetic profiles between the two central valleys. We concluded that the genetic differences observed between species (S. kamtschaticum vs. S. polytrichoides and H. ussuriense) are mainly due to differences in their distribution within the study area.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2013R1A1A2063524 and NRF-2013R1A1A3010892 to M.G.C. and M.Y.C., respectivelyPeer reviewe

    Could Fractional Exhaled Nitric Oxide Test be Useful in Predicting Inhaled Corticosteroid Responsiveness in Chronic Cough? A Systematic Review

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    © 2016 Background Fractional exhaled nitric oxide (FENO) is a safe and convenient test for assessing T H 2 airway inflammation, which is potentially useful in the management of patients with chronic cough. Objective To summarize the current evidence on the diagnostic usefulness of FENO for predicting inhaled corticosteroid (ICS) responsiveness in patients with chronic cough. Methods A systematic literature review was conducted to identify articles published in peer-reviewed journals up to February 2015, without language restriction. We included studies that reported the usefulness of FENO (index test) for predicting ICS responsiveness (reference standard) in patients with chronic cough (target condition). The data were extracted to construct a 2 × 2 accuracy table. Study quality was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. Results We identified 5 original studies (2 prospective and 3 retrospective studies). We identified considerable heterogeneities in study design and outcome definitions, and thus were unable to perform a meta-analysis. The proportion of ICS responders ranged from 44% to 59%. Sensitivity and specificity ranged from 53% to 90%, and from 63% to 97%, respectively. The reported area under the curve ranged from abou t 0.60 to 0.87; however, studies with a prospective design and a lower prevalence of asthma had lower area under the curve values. None measured placebo effects or objective cough frequency. Conclusions We did not find strong evidence to support the use of FENO tests for predicting ICS responsiveness in chronic cough. Further studies need to have a randomized, placebo-controlled design, and should use validated measurement tools for cough. Standardization would facilitate the development of clinical evidence

    Clinicopathological Risk Factors and Biochemical Predictors of Safe Discharge after Total Thyroidectomy and Central Compartment Node Dissection for Thyroid Cancer: A Prospective Study

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    To determine the clinicopathological risk factors and reliable biochemical predictors of the development of hypocalcemic symptoms after total thyroidectomy on the basis of serum calcium and intact parathyroid hormone (PTH) levels measured 1 hour after surgery, a prospective study was performed on 817 patients who underwent a total thyroidectomy with central compartment node dissection (CCND) due to well-differentiated thyroid cancer. We evaluated the correlations between hypocalcemic symptom development and clinicopathological factors. And the predictability for hypocalcemic symptom development of intact PTH cut-offs (<10 pg/mL and <20 pg/mL, resp.) according to serum calcium level subgroup was analyzed. Female gender (P<0.001) was the only independent risk factor for hypocalcemic symptom development in multivariate regression analysis. The negative predictive value (NPV) of intact PTH, signifying nondevelopment of hypocalcemic symptoms, was higher than the positive predictive value (PPV) which signified development of hypocalcemic symptoms. In addition, when we applied the different adoption of the intact PTH cut-off according to serum calcium level, we could obtain more increased NPVs. A female gender and the application of more specific cut-offs for intact PTH according to the serum calcium levels measured 1 hour after surgery may help the patients to be more safely discharged

    Phylogeography of the endangered orchids Cypripedium japonicum and Cypripedium formosanum in East Asia: Deep divergence at infra- and interspecific levels

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    To date, little is known about the past evolutionary trajectories of rare and endangered orchids native to mainland China, Japan, and Korea (the CJK region). In this study, we focus on two endangered orchids, Cypripedium japonicum (present in the three countries) and C. formosanum (endemic to Taiwan), to understand the divergence/speciation models that would have been operating in this group, including genetic diversity, geographic structure, and colonization pathways across the region. Using a combination of five cpDNA regions, we reconstructed phylogenetic trees and investigated the genetic diversity/structure of 20 populations. Ecological niche modeling was used to gain insight into the paleodistribution and dispersal corridors at the Last Glacial Maximum and to survey climatic niche differences. Populations from mainland China + Korea, Japan, and Taiwan formed three distinct monophyletic lineages and were placed into separate genetic clusters, agreeing with geographic barriers and species boundaries. Populations of C. japonicum in mainland China harbored the highest diversity, suggesting the presence of multiple glacial refugia. The Korean populations would have originated from either western/central or eastern China, probably using a dispersal corridor across the East China Sea shelf. The divergence of C. formosanum is proposed under an allopatric speciation model, also highly influenced by a climate niche shift. In the context of previous studies, a deep divergence in cpDNA sequences between Chinese + Korean and Japanese populations of C. japonicum may be taken as an example of the speciation events of the CJK flora since the late Neogene that have led to its current species richness.This study was supported by the Biodiversity Survey, Observation and Assessment Program of the Ministry of Ecology and Environment of China to HZT and by Basic Science Program through the National Research Foundation of Korea (NRF-2017R1A2B4012215) to MGC, and funded by the Ministry of Science and ICT of the Republic of Korea (NRF-2020R1I1A3074635) to MYC.INTRODUCTION MATERIALS AND METHODS Study species Population sampling DNA extraction cpDNA-PCR optimum primer selection cpDNA sequence alignment and assembly Haplotype distribution, phylogenetic analyses, and genetic diversity Genetic differentiation and structure Mismatch distribution analysis, neutrality detection, and demographic history ENM and population connectivity Niche comparisons in E-space RESULTS Haplotype distribution and phylogeny Genetic diversity Genetic differentiation and structure Mismatch distribution analysis, neutrality detection, and demographic history ENM and population connectivity Niche comparisons in E-space DISCUSSION Deep genetic and climatic divergence of Cypripedium sect. Flabellinervia in the CJK region: taxonomic considerations Haplotype and nucleotide diversity in Cypripedium sect. Flabellinervia: inference of glacial refugia and demographic history Origin of Korean populations of Cypripedium japonicum Origin of Cypripedium formosanum CONCLUSIONS AUTHOR CONTRIBUTIONS ACKNOWLEDGEMENTS Appendix 1: The cpDNA sequence information of Cypripedium sect. Flabellinervia deposited in the GenBank databas
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