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speciation with gene flow via cycles of isolation and migration:insights from multiple mangrove taxa

National Science Review 2019年第2期6卷 275-288页

作者： Ziwen He Xinnian Li Ming Yang Xinfeng Wang Cairong Zhong Norman C.Duke Chung-I Wu Suhua Shi State Key Laboratory of Biocontrol Guangdong Key Lab of Plant Resources Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education InstitutesSchool of Life Sciences Sun Yat-Sen University Department of Ecology and Evolution University of Chicago CAS Key Laboratory of Genome Sciences and Information Beijing Institute of GenomicsChinese Academy of Sciences Hainan Dongzhai Harbor National Nature Reserve Administration Centre for Tropical Water and Aquatic Ecosystem Research James Cook University

Allopatric speciation requiring an unbroken period of geographical isolation has been the standard model of neo-Darwinism. While doubts have been repeatedly raised, strict allopatry without any gene flow remains a plausible mechanism in most cases. To rigorously reject strict allopatry, genomic sequences superimposed on the geological records of a well-delineated geographical barrier are necessary. The Strait of Malacca,narrowly connecting the Pacific and Indian Ocean coasts, serves at different times either as a geographical barrier or a conduit of gene flow for coastal/marine species. We surveyed 1700 plants from 29 populations of 5 common mangrove species by large-scale DNA sequencing and added several whole-genome assemblies. speciation between the two oceans is driven by cycles of isolation and gene flow due to the fluctuations in sea level leading to the opening/closing of the Strait to ocean currents. Because the time required for speciation in mangroves is longer than the isolation phases, speciation in these mangroves has proceeded through many cycles of mixing-isolation-mixing, or MIM, cycles. The MIM mechanism, by relaxing the condition of no gene flow, can promote speciation in many more geographical features than strict allopatry can. Finally, the MIM mechanism of speciation is also efficient, potentially yielding mn(m > 1) species after n cycles.

关键词： speciation gene flow allopatry geographical isolation mangrove

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Extensive gene flow in secondary sympatry after allopatric speciation

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National Science Review 2022年第12期9卷 24-36页

作者： Xinfeng Wang Ziwen He Zixiao Guo Ming Yang Shaohua Xu Qipian Chen Shao Shao Sen Li Cairong Zhong Norman C.Duke Suhua Shi State Key Laboratory of Biocontrol Guangdong Key Laboratory of Plant Resources School of Life SciencesSouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Sun Yat-sen University Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering School of Life Sciences Fudan University Department of Laboratory Medicine& Pathology University of Washington Hainan Academy of Forestry (Hainan Academy of Mangrove) Centre for Tropical Water and Aquatic Ecosystem Research James Cook University

In the conventional view,species are separate gene pools delineated by reproductive isolation(RI).In an alternative view,species may also be delineated by a small set of ’speciation genes’ without full RI,a view that has gained broad acceptance.A recent survey,however,suggested that the extensive literature on’speciation with gene flow’ is mostly(if not all) about exchanges in the early stages of speciation.There is no definitive evidence that the observed gene flow actually happened after speciation is completed.Here,we wish to know whether ’good species’(defined by the ’secondary sympatry’ test) do continue to exchange genes and,importantly,under what conditions such exchanges can be observed.De novo whole-genome assembly and re-sequencing of individuals across the range of two closely related mangrove species(Rhizophora mucronata and R. stylosa) reveal the genomes to be well delineated in allopatry.They became sympatric in northeastern Australia but remain distinct species.Nevertheless,their genomes harbor～4000-10 000 introgression blocks averaging only about 3-4 Kb.These fine-grained introgressions indicate continual gene flow long after speciation as non-introgressable ’genomic islets,’～1.4 Kb in size,often harbor diverging genes of flower or gamete development.The fine-grained introgression in secondary sympatry may help settle the debate about sympatric vs.micro-allopatric speciation.In conclusion,true’good species’ may often continue to exchange genes but the opportunity for detection is highly constrained.

关键词： mangroves population genomics speciation introgression species hybridization

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speciation of organomercury compounds by capillary electrophoresis with pre-column derivatization and on-line stacking

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Chinese Chemical Letters 2019年第3期30卷 650-652页

作者： Dandan Cao Yongguang Yin Bin He State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences

Simultaneous separation and detection of three organomercury species, namely methylmercury(MeHg),ethylmercury(EtHg), and phenylmercury(PhHg), was performed by using capillary electrophoresis(CE)with UV detection. Pre-column derivatization with thiosalicylic acid and on-line salt-induced stacking significantly improved the detection performance. Buffer pH, ion strength, and additive were optimized for CE separation, concentration of NaCl in sample solution and injection time were optimized for on-line stacking. The limits of detection were 76.9,83.0 and 76.4 μg/L for PhHg, EtHg and MeHg, respectively. The developed method was validated by certified reference material and liquid chromatography-atomic fluorescence spectroscopy, which suggests this method could be useful in the speciation of organomercury compounds in biological samples.

关键词： Capillary electrophoresis Mercury speciation Derivatization On-line stacking

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speciation, sources, and risk assessment of heavy metals in suburban vegetable garden soil in Xianyang City, Northwest China

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Frontiers of Earth Science 2018年第2期12卷 397-407页

作者： Lijun WANG Wendong TAO Richard C. SMARDON Xue XU Xinwei LU Department of Environmental Science College of Tourism and Environment Shaanxi Normal University Xi'an 710119 China College of Environmental Science and Forestry State University of New York NY 13201 USA

Intensive anthropogenic activities can lead to soil heavy metal contamination resulting in potential risks to the environment and to human health. To reveal the concentrations, speciation, sources, pollution level, and ecological risk of heavy metals in vegetable garden soil, a total of 136 soil samples were collected from three vegetable production fields in the suburbs of Xianyang City, Northwest China. These samples were analyzed by inductively coupled plasma- atomic emission spectrometry and atomic fluorescence spectrometry. The results showed that the mean concentrations of Cd, Co, Cu, Mn, Pb, Zn, and Hg in vegetable garden soil were higher than the corresponding soil element background values of Shaanxi Province. The heavy metals studied in vegetable garden soil were primarily found in the residual fraction, averaging from 31.26% (Pb) to 90.23% (Cr). Considering the non-residual fractions, the mobility or potential risk was in the order of Pb (68.74%)>Co (60.54%)>Mn (59.28%) >Cd (53.54%) ≫Ni (23.36%) >Zn (22.73%)>Cu (14.93%)>V (11.81%)>Cr (9.78%). Cr, Mn, Ni, V, and As in the studied soil were related to soilforming parent materials, while Cu, Hg, Zn, Cd, Co, and Pb were associated with the application of plastic films, fertilizers, and pesticides, as well as traffic emissions and industrial fumes. Cr, Ni, V, and As presented low contamination levels, whereas Co, Cu, Mn, Pb, and Zn levels were moderate, and Cd and Hg were high. Ecological risk was low for Co, Cr, Cu, Mn, Pb, Zn, and As, with high risk observed for Cd and Hg. The overall pollution level and ecological risk of these heavy metals were high.

关键词： heavy metal speciation source pollution level ecological risk vegetable garden soil

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Stability of selenium and its speciation analysis in water using automatic system separation and HR-ICP-MS measurement

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Chinese Chemical Letters 2022年第7期33卷 3444-3450页

作者： Junqiang Yang Yawen Chen Keliang Shi Kesheng Hu Run Li Xiaoqing Gao Qian Wang Weibo Zhang Yun Zhou Yanyun Wang Jiangang He Tonghuan Liu Xiaolin Hou Frontier Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Beijing National Laboratory for Molecular Sciences Fundamental Science Laboratory on Radiochemistry&Radiation ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Key Laboratory of Special Function Materials and Structure Design Ministry of EducationLanzhou UniversityLanzhou 730000China CNNC Lanzhou Uranium Enrichment Co. Ltd.Lanzhou 730000China Environmental Monitor Center of Gansu Province Lanzhou 730000China

A simple and convenient method has been developed for the pre-concentration and separation of inorganic selenium species from environmental water samples using anion exchange chromatographic column combined with high resolution inductively coupled plasma mass spectrometry(HR-ICP-MS)measurement.^(75)Se(Ⅳ) and ^(75)Se(Ⅵ)were prepared and used as tracers during the experiments.The volatility of selenium during solution evaporation was investigated to establish a reliable water samples pretreatment procedure.The parameters which affect the uptake of Se(Ⅳ)and Se(Ⅵ)on Dowex1×8 resin was optimized and the procedure for Se(Ⅳ)and Se(Ⅵ)separation was proposed.Both Se(Ⅳ)and Se(Ⅵ)are retained on the column in natural or alkaline solution with high distribution coefficient.The successive gradient elution of pre-concentrated species of selenium with HNO_(3)solution allows to differentiate between them.Se(Ⅳ)and Se(Ⅵ)finally were eluted with 0.05 mol/L HNO_(3) and 5.0 mol/L HNO_(3),respectively.The proposed method has been successfully verified using the certified reference materials(CRMs)of real water samples,and spiked recoveries for real samples were 98%-104%with 5%relative standard deviations(RSDs).The developed procedure is proved to be reliable and can be used for the rapid determination of selenium species in environmental water samples.

关键词： Inorganic selenium speciation Automatic system separation Rapid determination Water sample

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Distribution and chemical speciation of arsenic in different sized atmospheric particulate matters

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Journal of Environmental Sciences 2021年第10期33卷 1-7页

作者： Jin Xie Xiao-Dong Niu Jiao-Jiao Xie Kai-Qiang He Meng-Dan Shi Su-Juan Yu Chun-Gang Yuan Jing-Fu Liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science&EngineeringNorth China Electric Power UniversityBaoding 071000China

The distribution and chemical speciation of arsenic(As)in different sized atmospheric particulate matters(PMs),including total suspended particles(TSP),PM_(10),and PM_(2.5),collected from Baoding,China were analyzed.The average total mass concentrations of As in TSP,PM_(10),and PM_(2.5)were 31.5,35.3,and 54.1μg/g,respectively,with an order of PM_(2.5)>PM_(10)>TSP,revealing that As is prone to accumulate on fine particles.Due to the divergent toxicities of different As species,speciation analysis of As in PMs is further conducted.Most of previous studies mainly focused on inorganic arsenite(iAs^(Ⅲ)),inorganic arsenate(iAs^(Ⅴ)),monomethylarsonate(MMA),and dimethylarsinate(DMA)in PMs,while the identification and sensitive quantification of trimethylarsine oxide(TMAO)were rarely reported.In this study,a high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry system was optimized for As speciation including TMAO in PMs.An anion exchange column was used to separate MMA,DMA and iAs^(Ⅴ),while a cation exchange column to separate TMAO and iAs^(Ⅲ).Results showed that iAs^(Ⅴ) was the dominate component in all the samples,corresponding to a portion of 79.2%±9.3%of the total extractable species,while iAs^(Ⅲ),TMAO and DMA made up the remaining 21%.Our study demonstrated that iAs^(Ⅲ) accounted for about 14.4%±11.4%of the total extracted species,with an average concentration of 1.7±1.6 ng/m^(3).It is worth noting that TMAO was widely present in the samples(84 out of 97 samples),which supported the assumption that TMAO was ubiquitous in atmospheric particles.

关键词： Arsenic Particulate matters speciation Size distribution

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Effects of substrate types on the transformation of heavy metal speciation and bioavailability in an anaerobic digestion system

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Journal of Environmental Sciences 2021年第3期33卷 361-372页

作者： Xiarong Zheng Kuanhuai Wu Pengju Sun Siyu Zhouyang Yuanpeng Wang Haitao Wang Yanmei Zheng Qingbiao Li Department of Chemical and Biochemical Engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Food and Biological Engineering Jimei UniversityXiamen 361021China

Chemical speciation can fundamentally affect the potential toxicity and bioavailability of heavy metals.The transformation of heavy metal speciation and change of bioavailability were investigated in an anaerobic digestion(AD)system using four different substrates(pig manure(PM),cattle manure(CAM),chicken manure(CHM)and rice straw(RS)).The results obtained indicated that the total contents of heavy metals in PM,CHM and GAM were higher than in RS and decreased in the order Zn>Cu>Ni>Pb>As>Cd in all substrates.Moreover,the speciation with the largest proportion for each heavy metal was the same both in the different substrates and the biogas residues.Among them,Zn,Ni,Cd and As were mainly in the reducible fraction(F2),while Cu was mainly in the oxidizable fraction(F3)and Pb occurred predominantly in the residual fraction(F4).Our results further indicated that the AD process had a greater effect on the speciation of heavy metals in CHM and PM,but less on CAM and RS.The rates of change in bioavailability followed the order PM>CHM>CAM>RS.Changes in organic matter,humic acid or local metal ion environment as a result of AD were inferred as likely mechanisms leading to the transformation of heavy metal speciation.These results enhanced our understanding of the behavior of heavy metals in AD and provided a new perspective for the treatment and disposal of the substrates.

关键词： Anaerobic digestion Heavy metal speciation Bioavailability

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Genes and speciation: is it time to abandon the biological species concept?

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National Science Review 2020年第8期7卷 1387-1397页

作者： Xinfeng Wang Ziwen He Suhua Shi Chung-I Wu State Key Laboratory of Biocontrol Guangdong Key Lab of Plant Resources School of Life Sciences Sun Yat-Sen University Department of Ecology and Evolution University of Chicago

The biological species concept(BSC) is the cornerstone of neo-Darwinian thinking. In BSC, species do not exchange genes either during or after speciation. However, as gene flow during speciation is increasingly being reported in a substantial literature, it seems time to reassess the revered, but often doubted, BSC.Contrary to the common perception, BSC should expect substantial gene flow at the onset of speciation, not least because geographical isolation develops gradually. Although BSC does not stipulate how speciation begins, it does require a sustained period of isolation for speciation to complete its course. Evidence against BSC must demonstrate that the observed gene flow does not merely occur at the onset of speciation but continues until its completion. Importantly, recent genomic analyses cannot reject this more realistic version of BSC, although future analyses may still prove it wrong. The ultimate acceptance or rejection of BSC is not merely about a historical debate; rather, it is about the fundamental nature of species – are species(and, hence, divergent adaptations) driven by a relatively small number of genes, or by thousands of them? Many levels of biology, ranging from taxonomy to biodiversity, depend on this resolution.

关键词： speciation species concept gene flow geographical isolation allopatry

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Effect of natural organic matter on thallium and silver speciation

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Journal of Environmental Sciences 2020年第7期32卷 185-192页

作者： Loïc A.Martin Caroline Simonucci Sétareh Rad Marc F.Benedetti Universitéde Paris Institut de physique du globe de ParisCNRSF-75005 ParisFrance IRSN PSE-ENV/SIRSE/LER-NordBP 1792262 Fontenay-aux-Roses CedexFrance Catchment and Eco-Hydrology Research Group Luxembourg Institute of Science and TechnologyL-4422 BelvauxLuxembourg BRGM Unitéde Géomicrobiologie et Monitoring Environnemental45060 Orléans Cedex 2France

Natural organic matter(NOM)is known to play an important role in the transport and binding of trace metal elements in aquatic and soil systems.Thallium is a pollutant for which the extent of the role played by NOM is poorly known.Consequently,this study investigates thallium(Ⅰ)and its complexation to a purified humic substance as proxy for NOM.Experiments were performed with the Donnan Membrane Technique to separate,for the first time,the free Tl^+ion from its complexed form in the bulk solution.Various pH and concentrations were investigated at constant ionic strength and constant NOM proxy concentrations in solution.Experimental results were described with NICA-Donnan model.Thallium complexation was compared to silver complexation using literature data and using the same NICA-Donnan formalism.Parameters for these two cations(Tl^+and Ag^+)are reported in this article,for the first time.Results display low thallium complexation to the NOM proxy while silver competes with divalent cations for the NOM binding sites.Calculated speciation for dissolved thallium highlights the dominance of free thallium(Tl^+)in solution whereas Tl-NOM complexes contribute roughly 15%to total Tl(Ⅰ)species in river and lake type waters.Similar results are obtained for soil solutions,Tl-bound to NOM<30%of total,from UK soils with different land use and geochemistry.

关键词： Thallium Organic matter speciation NICA-Donnan model Soil Water

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speciation and bioaccessibility of lead and cadmium in soil treated with metal-enriched Indian mustard leaves

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Journal of Environmental Sciences 2011年第4期23卷 624-632页

作者： Yanshan Cui Jin Fu Xiaochen Chen College of Resources and Environment Graduate University of Chinese Academy of Sciences Beijing 100049 China.

Indian mustard （Brassica juncea （L.） Czern.） has shown good potential for the phytoremediation of soil contaminated with heavy metals. However, there is little information about the speciation and bioaccessibility of heavy metals in soil during the decomposition of metal-rich Indian mustard leaves. Incubation experiments （1-, 3-, and 6-month） were carried out in Beijing and Hunan soil with metal-rich Indian mustard leaves addition （1% and 3%） and the effects of mustard leaves addition on the speciation and bioaccessibility of heavy metals were studied. The results showed that the addition of mustard leaves led to significant increases in pH and DOC in the Hunan soil. Both 1% and 3% of mustard leaf amendment caused the percentage of the exchangeable （F1）, precipitated with carbonates （F2）, bound to Fe/Mn oxides （F3） and bound to organic matter （F4） fractions of Pb and Cd to increase dramatically, while the percentage of the residual fraction （F5） of Cd and Pb significantly dropped in both Beijing and Hunan soils. Mustard leaf addition caused the bioaccessibility of Pb to decrease in the gastric phase, whereas the values increased in the small intestinal phase. The Cd bioaccessibility increased with mustard leaf addition in both the gastric and small intestinal phases. In conclusion, the metal-enriched mustard leaves addition induces Pb and Cd concentrations and their mobility increasing in the Beijing and Hunan soils. Therefore, heavy metal risk in metal-enriched plant leaves should be considered in phytoremediation system in which heavy metal might be brought back to soil and changed over time.

关键词： lead cadmium speciation bioaccessibility decomposition

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