[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea sn...[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.展开更多
Objective Poisonous plants are a deadly threat to public health in China. The traditional clinical diagnosis of the toxic plants is inefficient, fallible, and dependent upon experts. In this study, we tested the perfo...Objective Poisonous plants are a deadly threat to public health in China. The traditional clinical diagnosis of the toxic plants is inefficient, fallible, and dependent upon experts. In this study, we tested the performance of DNA barcodes for identification of the most threatening poisonous plants in China. Methods Seventy-four accessions of 27 toxic plant species in 22 genera and 17 families were sampled and three DNA barcodes(matK, rbcL, and ITS) were amplified, sequenced and tested. Three methods, Blast, pairwise global alignment(PWG) distance, and Tree-Building were tested for discrimination power. Results The primer universality of all the three markers was high. Except in the case of ITS for Hemerocallis minor, the three barcodes were successfully generated from all the selected species. Among the three methods applied, Blast showed the lowest discrimination rate, whereas PWG Distance and Tree-Building methods were equally effective. The ITS barcode showed highest discrimination rates using the PWG Distance and Tree-Building methods. When the barcodes were combined, discrimination rates were increased for the Blast method. Conclusion DNA barcoding technique provides us a fast tool for clinical identification of poisonous plants in China. We suggest matK, rbcL, ITS used in combination as DNA barcodes for authentication of poisonous plants.展开更多
This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult s...This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI (cytochrome oxidase subunitⅠ) are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA (universal plastid amplicon, domain V of 23S rRNA), and ITS (nuclear internal transcribed spacer) were employed to analyze common species of intertidal red seaweeds in Qingdao (119.3 -121 E, 35.35 -37.09 N). The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.展开更多
Molecular markers provide a useful method for genotype characterization and allow a high precision determination of the genetic relationship between cultivars and varieties. A system based on DNA sequences—which is k...Molecular markers provide a useful method for genotype characterization and allow a high precision determination of the genetic relationship between cultivars and varieties. A system based on DNA sequences—which is known as DNA barcoding—will choose one or several standard loci which can be sequenced and compared to differentiate between species. In this research, the ITS, matK, and trnH-psbA sequences were evaluated for the molecular identification of seven F. carica genotypes, generating complete sequences for the first two loci, but unable to produce bidirectional sequences by using the trnH-psbA sequence. The ITS sequence presented the highest variation rates, while the phylogeny constructed with the matK sequence obtained the highest percentage of solved monophyletic groups. Through Pearson’s correlation analysis, it was possible to determine the existence of a significant correlation between the ITS region and psbA-trnH, and the matK and psbA-trnH sequences, but not between ITS and matK. The phylogenies constructed with the ITS + matK barcodes and ITS + matK + psbA-trnH presented the highest percentage for resolution. However, considering the cost efficiency and the facilitated recovery by using PCR, the matK + ITS combination is recommended.展开更多
A total of 142 specimens of Ceramiales(Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species,14 genera,and f...A total of 142 specimens of Ceramiales(Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species,14 genera,and four families. Cluster analyses show that the specimens had a high diversity for the three DNA markers,namely,partial large subunit r RNA gene(LSU),universal plastid amplicon(UPA),and partial mitochondrial cytochrome c oxidase subunit I gene(COI). No intraspecific divergence was found in our collection for these markers,except for a 1–3 bp divergence in the COI of Ceramium kondoi,Symphyocladia latiuscula,and Neosiphonia japonica. Because short DNA markers were used,the phylogenetic relationships of higher taxonomic levels were hard to evaluate with poor branch support. More than half species of our collection failed to find their matched sequences owing to shortage information of DNA barcodes for macroalgae in Gen Bank or BOLD(Barcode of Life Data) Systems. Three specimens were presumed as H eterosiphonia crispella by cluster analyses on DNA barcodes assisted by morphological identification,which was the first record in the investigated area,implying that it might be a cryptic or invasive species in the coastal area of northwestern Yellow Sea. In the neighbor-joining trees of all three DNA markers,H eterosiphonia japonica converged with D asya spp. and was distant from the other Heterosiphonia spp.,implying that H. japonica had affinities to the genus Dasya. The LSU and UPA markers amplified and sequenced easier than the COI marker across the Ceramiales species,but the COI had a higher ability to discriminate between species.展开更多
[Objective]Xanthium plants( non-Chinese species) are quarantine pests in China. This study aimed to distinguish and identify seven Xanthium species using ITS2 sequence as DNA barcode.[Method]ITS2 gene was amplified us...[Objective]Xanthium plants( non-Chinese species) are quarantine pests in China. This study aimed to distinguish and identify seven Xanthium species using ITS2 sequence as DNA barcode.[Method]ITS2 gene was amplified using universal primers to obtain ITS2 sequences of seven Xanthium species,which were then sequenced. ITS2 sequences of seven Xanthium species were compared and analyzed by MEGA 5. 1 software,and the phylogenetic tree was constructed.[Result]A total of 242 variable sites were found in ITS2 sequences of Xanthium species,including 12 singleton variable sites.[Conclusion]Xanthium species can be distinguished and identified based on ITS2 sequences.展开更多
Phytophtkora is genus of plant-damaging Oomycetes,whose member species are capable of causing enormous economic losses on crops worldwide.In the present study,four candidate genes ITS,CO1,EF-1α and β-tubulin were te...Phytophtkora is genus of plant-damaging Oomycetes,whose member species are capable of causing enormous economic losses on crops worldwide.In the present study,four candidate genes ITS,CO1,EF-1α and β-tubulin were tested using 123 strains of 80 species of Phytophthora to investigate the feasibility of serving as DNA barcoding markers.The results showed that among the four candidate genes,ITS and CO1 had the highest success rate of PCR amplification and sequencing,up to 100%and 96.7%.There were obvious barcode gaps in ITS,CO1 and β-tubulin,but their frequency distributions of intra-and interspecific genetic distances were slightly overlapped.Wilcoxon rank sum test on intraspecific genetic distances of the four genes showed ITS = CO1 = β-tubulin = EF-1α,indicating they had the same effect on intraspecific discrimination,while the test on interspecific genetic distances of the four genes showed ITS > CO1 > β-tubulin > EF-1α.In summary,ITS and CO1 should be used in combination as the primary barcodes,β-tubulin as the complementary barcode for the identification of 11 quarantine Phytophthora species.展开更多
The novelty and suitability of the mitochondrial gene CO1 in DNA barcoding as a reliable identification tool in animal species are undisputed. This is attributed to its standardized sequencing segment of the mitochond...The novelty and suitability of the mitochondrial gene CO1 in DNA barcoding as a reliable identification tool in animal species are undisputed. This is attributed to its standardized sequencing segment of the mitochondrial cytochrome c oxidase-1 gene (CO1) which has the necessary universality and variability making it a generally acceptable barcode region. CO1 is a haploid single locus that is uniparentally-inherited. Protein-coding regions are present in high-copy numbers making it an ideal barcode. The mitochondrial oxidase subunit I (COI) gene is a robust barcode with a suitable threshold for delineating animals and is not subject to drastic length variation, frequent mononucleotide repeats or microinversions. However, a low nucleotide substitution rate of plant mitochondrial genome [mtDNA] precludes the use of CO1 as a universal plant DNA barcode and makes the search for alternative barcode regions necessary. Currently, there exists no universal barcode for plants. The plastid region reveals leading candidate loci as appropriate DNA barcodes yet to be explored in biodiversity studies in Kenya. Four of these plastid regions are portions of coding genes (matK, rbcL, rpoB, and rpoC1), and three noncoding spacers (atpF-atpH, trnH-psbA, and psbK-psbL) which emerge as ideal candidate DNA loci. While different research groups propose various combinations of these loci, there exists no consensus;the lack thereof impedes progress in getting a suitable universal DNA barcode. Little research has attempted to investigate and document the applicability and extend of effectiveness of different DNA regions as barcodes to delineate cowpea at subspecies level. In this study we sought to test feasibility of the seven putative candidate DNA loci singly and in combination in order to establish a suitable single and multi-locus barcode regions that can have universal application in delineating diverse phylogeographic groups of closely related Kenyan cowpea variants. In this study, our focus was based on genetic parameters including analyses of intra- and infra-specific genetic divergence based on intra- and infra-specific K2P distances;calculation of Wilcoxon signed rank tests of intra-specific divergence among loci and coalescence analyses to delineate independent genetic clusters. Knowledge of DNA candidate loci that are informative will reveal the suitability of DNA barcoding as a tool in biodiversity studies. Results of this study indicate that: matK, trnH-psbA, psbK-psbL, and rbcL are good barcodes for delineating intra and infraspecific distances at single loci level. However, among the combinations, matK + trnH-psbA, rpoB + atpF-atpH + matK are the best barcodes in delineating cowpea subvariants. rbcL gene can be a suitable barcode marker at single locus level, but overall, multi locus approach appears more informative than single locus approach. The present study hopes to immensely contribute to the scanty body of knowledge on the novelty of DNA barcoding in cataloguing closely related cowpea variants at molecular level and hopes to open up future research on genomics and the possibility of use of conserved regions within DNA in inferring phylogenetic relationships among Kenyan cowpea variants.展开更多
The desert plant Rhazya stricta has anticancer and antimicrobial properties, and is widely used in indigenous medicines of Saudi Arabia. However, the therapeutic benefits rely on an accurate identification of this spe...The desert plant Rhazya stricta has anticancer and antimicrobial properties, and is widely used in indigenous medicines of Saudi Arabia. However, the therapeutic benefits rely on an accurate identification of this species. The authenticity of R. stricta and other medicinal plants and herbs procured from local markets can be questionable due to a lack of clear phenotypic traits. DNA barcoding is an emerging technology for rapid and accurate species identification. In this study, six candidate chloroplastid barcodes were investigated for the authentication of R. stricta. We compared the DNA sequences from fifty locally collected and five market samples of R. stricta with database sequences of R. stricta and seven closely related species. We found that the coding regions matK, rbcL, rpoB, and rpoC1 were highly similar among the taxa. By contrast, the intergenic spacers psbK-psbI and atpF-atpH were variable loci distinct for the medicinal plant R. stricta. psbK-psbI clearly discriminated R. stricta samples as an efficient single locus marker, whereas a two-locus marker combination comprising psbK-psbI + atpF-atpH was also promising according to results from the Basic Local Alignment Search Tool and a maximum likelihood gene tree generated using PHyML. Two-dimensional DNA barcodes (i.e., QR codes) for the psbK-psbI and psbK-psbI + atpF-atpH regions were created for the validation of fresh or dried R. stricta samples.展开更多
[Objectives] To identify ITS2 barcode of Lablab Semen Album and its adulterants,and provide a new method for the identification of Lablab Semen Album. [Methods] The ITS2 sequence was amplified by PCR and sequenced bi-...[Objectives] To identify ITS2 barcode of Lablab Semen Album and its adulterants,and provide a new method for the identification of Lablab Semen Album. [Methods] The ITS2 sequence was amplified by PCR and sequenced bi-directionally. After splicing by Codon Code Aligner,the data were processed with the aid MEGA software to construct the cluster dendrogram( neighbor-joining,NJ tree). [Results]The ITS2 sequence of Lablab Semen Album had length of 218 bp; the constructed cluster dendrogram indicated that all species were monophyletic and could be distinguished from other species. [Conclusions] The ITS2 barcode can be used for rapid identification of Lablab Semen Album and its adulterants and this experiment further verified that DNA barcode technology is effective in identification of traditional Chinese medicines.展开更多
Because of its importance as a food source, Nemipterus japonicus(Bloch, 1791)(Nemipteridae) or Japanese threadfin bream is the best studied of these taxa, and numerous investigations have examined its fisheries, its b...Because of its importance as a food source, Nemipterus japonicus(Bloch, 1791)(Nemipteridae) or Japanese threadfin bream is the best studied of these taxa, and numerous investigations have examined its fisheries, its biology and biochemistry. Despite such intensive work, the taxonomic status of N. japonicus has never been seriously questioned and it is regarded as a common species, widely distributed throughout the Indo-Western Pacific Ocean. In fact, Bloch's description of the type specimen of N. japonicus has ambiguous collection data and lacks a designation for the type locality, though it is probably Java. In this paper, DNA barcode results based on COI gene support the existence of two geographically separated lineages of the Japanese threadfin bream, both being an Indian Ocean and western Pacific lineage, with 2.7% sequence divergence, and the results indicate a possible existing of some cryptic species. The two lineages also possess a diagnostic difference in their belly color, with specimens in the South China Sea having a silver belly, while those from the Indian Ocean isolate specimen have a yellow coloration. Based upon new collections from the South China Sea, this species from the western Pacific is morphologically redescribed and its details of DNA barcode diversity are shown for the future investigations.展开更多
Chrysopidae are a family of Neuroptera of significant importance in biocontrol against agricultural pests because of their predatory larvae.Currently,the taxonomy of Chrysopidae lacks a comprehensive revision,which im...Chrysopidae are a family of Neuroptera of significant importance in biocontrol against agricultural pests because of their predatory larvae.Currently,the taxonomy of Chrysopidae lacks a comprehensive revision,which impedes the exploration of species diversity as well as the selection and the conservation of green lacewings as biocontrol agents.We have established a DNA barcode reference library of the Chinese green lacewings based on an approximately complete sampling(95.63%)in 25 of the 34 provincial regions in China,comprising 1119 barcodes of 25 genera and 197 species(representing 85%genera and 43.62%species from China).Combining other 1049 high quality green lacewing DNA barcodes,we first inferred the optimal threshold of interspecific genetic divergence(1.87%)for successful species identification in multiple simulated scenarios based on present data.We further inferred the threshold of genetic divergence(7.77%)among genera with biocontrol significance.The inference and performance of the threshold appears to be mainly associated with the completeness of sampling,the proportion of closely related species,and the analytical approaches.Six new combinations,Apertochrysa platypa(Yang&Yang,1991)comb.nov.,Apertochrysa shennongana(Yang&Wang,1990)comb.nov.,Apertochrysa pictifacialis(Yang,1988)comb.nov.,Apertochrysa helana(Yang,1993)comb.nov.,Plesiochrysa rosulata(Yang&Yang,2002)comb.nov.,and Signochrysa hainana(Yang&Yang,1991),are proposed according to integrative species delimitation.Our library and optimal threshold will effectively facilitate the exploration of species diversity of green lacewings.Our study also provides a methodological reference in molecular delimitation of other insects.展开更多
基金Supported by Hainan Provincial Natural Science Foundation of China,High-level Talent Project(321RC587),Classification of sea snakes in the South Sea China based on molecular Systematics,morphology and climate modelSpecial Scientific Research Trial Production Project of Sanya City(2016KS05),Identification of sea snake species and construction of DNA barcoding based on molecular systematics.
文摘[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.
基金supported by the Fundamental Research Funds for the Central Universities(grant no.TD2012-04)the Scientific Research Foundation of the State Human Resource Ministry and the Education Ministry for Returned Chinese Scholars(to L.Xie)+2 种基金the State Key Laboratory Program from the State Key Laboratory of Systematic and Evolutionary Botany(grant no.LSEB2011-07)the Main Direction Program of Knowledge Innovation of the Chinese Academy of Sciences(grant no.KSCX2-EW-Z-1)the National Natural Science Foundation of China(grant nos.31170201,81072317,31110103911)
文摘Objective Poisonous plants are a deadly threat to public health in China. The traditional clinical diagnosis of the toxic plants is inefficient, fallible, and dependent upon experts. In this study, we tested the performance of DNA barcodes for identification of the most threatening poisonous plants in China. Methods Seventy-four accessions of 27 toxic plant species in 22 genera and 17 families were sampled and three DNA barcodes(matK, rbcL, and ITS) were amplified, sequenced and tested. Three methods, Blast, pairwise global alignment(PWG) distance, and Tree-Building were tested for discrimination power. Results The primer universality of all the three markers was high. Except in the case of ITS for Hemerocallis minor, the three barcodes were successfully generated from all the selected species. Among the three methods applied, Blast showed the lowest discrimination rate, whereas PWG Distance and Tree-Building methods were equally effective. The ITS barcode showed highest discrimination rates using the PWG Distance and Tree-Building methods. When the barcodes were combined, discrimination rates were increased for the Blast method. Conclusion DNA barcoding technique provides us a fast tool for clinical identification of poisonous plants in China. We suggest matK, rbcL, ITS used in combination as DNA barcodes for authentication of poisonous plants.
基金supported by the National Special Research Fund for Non-Profit Sector (Agriculture) (No. 200903030)the National Natural Science Foundation of China (No.41176135)
文摘This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI (cytochrome oxidase subunitⅠ) are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA (universal plastid amplicon, domain V of 23S rRNA), and ITS (nuclear internal transcribed spacer) were employed to analyze common species of intertidal red seaweeds in Qingdao (119.3 -121 E, 35.35 -37.09 N). The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.
文摘Molecular markers provide a useful method for genotype characterization and allow a high precision determination of the genetic relationship between cultivars and varieties. A system based on DNA sequences—which is known as DNA barcoding—will choose one or several standard loci which can be sequenced and compared to differentiate between species. In this research, the ITS, matK, and trnH-psbA sequences were evaluated for the molecular identification of seven F. carica genotypes, generating complete sequences for the first two loci, but unable to produce bidirectional sequences by using the trnH-psbA sequence. The ITS sequence presented the highest variation rates, while the phylogeny constructed with the matK sequence obtained the highest percentage of solved monophyletic groups. Through Pearson’s correlation analysis, it was possible to determine the existence of a significant correlation between the ITS region and psbA-trnH, and the matK and psbA-trnH sequences, but not between ITS and matK. The phylogenies constructed with the ITS + matK barcodes and ITS + matK + psbA-trnH presented the highest percentage for resolution. However, considering the cost efficiency and the facilitated recovery by using PCR, the matK + ITS combination is recommended.
基金Supported by the Public Science and Technology Research Funds Projects of Ocean(Nos.201105021,201305030)the National Natural Science Foundation of China(No.41276137)
文摘A total of 142 specimens of Ceramiales(Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species,14 genera,and four families. Cluster analyses show that the specimens had a high diversity for the three DNA markers,namely,partial large subunit r RNA gene(LSU),universal plastid amplicon(UPA),and partial mitochondrial cytochrome c oxidase subunit I gene(COI). No intraspecific divergence was found in our collection for these markers,except for a 1–3 bp divergence in the COI of Ceramium kondoi,Symphyocladia latiuscula,and Neosiphonia japonica. Because short DNA markers were used,the phylogenetic relationships of higher taxonomic levels were hard to evaluate with poor branch support. More than half species of our collection failed to find their matched sequences owing to shortage information of DNA barcodes for macroalgae in Gen Bank or BOLD(Barcode of Life Data) Systems. Three specimens were presumed as H eterosiphonia crispella by cluster analyses on DNA barcodes assisted by morphological identification,which was the first record in the investigated area,implying that it might be a cryptic or invasive species in the coastal area of northwestern Yellow Sea. In the neighbor-joining trees of all three DNA markers,H eterosiphonia japonica converged with D asya spp. and was distant from the other Heterosiphonia spp.,implying that H. japonica had affinities to the genus Dasya. The LSU and UPA markers amplified and sequenced easier than the COI marker across the Ceramiales species,but the COI had a higher ability to discriminate between species.
基金Supported by Science and Technology Project of Jiangsu Entry-Exit Inspection and Quarantine Bureau(2012KJ54)
文摘[Objective]Xanthium plants( non-Chinese species) are quarantine pests in China. This study aimed to distinguish and identify seven Xanthium species using ITS2 sequence as DNA barcode.[Method]ITS2 gene was amplified using universal primers to obtain ITS2 sequences of seven Xanthium species,which were then sequenced. ITS2 sequences of seven Xanthium species were compared and analyzed by MEGA 5. 1 software,and the phylogenetic tree was constructed.[Result]A total of 242 variable sites were found in ITS2 sequences of Xanthium species,including 12 singleton variable sites.[Conclusion]Xanthium species can be distinguished and identified based on ITS2 sequences.
基金Supported by Science and Technology Plan Project of Shenzhen Entry-Exit Inspection and Quarantine Bureau(SZ2015101)National Key Technology Research and Development Program of China during the 12~(th)Five-Year Plan Period(2012BAK11B06)Science and Technology Plan Project of General Administration of Quality Supervision,Inspection and Quarantine of People's Republic of China(2016IK239)
文摘Phytophtkora is genus of plant-damaging Oomycetes,whose member species are capable of causing enormous economic losses on crops worldwide.In the present study,four candidate genes ITS,CO1,EF-1α and β-tubulin were tested using 123 strains of 80 species of Phytophthora to investigate the feasibility of serving as DNA barcoding markers.The results showed that among the four candidate genes,ITS and CO1 had the highest success rate of PCR amplification and sequencing,up to 100%and 96.7%.There were obvious barcode gaps in ITS,CO1 and β-tubulin,but their frequency distributions of intra-and interspecific genetic distances were slightly overlapped.Wilcoxon rank sum test on intraspecific genetic distances of the four genes showed ITS = CO1 = β-tubulin = EF-1α,indicating they had the same effect on intraspecific discrimination,while the test on interspecific genetic distances of the four genes showed ITS > CO1 > β-tubulin > EF-1α.In summary,ITS and CO1 should be used in combination as the primary barcodes,β-tubulin as the complementary barcode for the identification of 11 quarantine Phytophthora species.
文摘The novelty and suitability of the mitochondrial gene CO1 in DNA barcoding as a reliable identification tool in animal species are undisputed. This is attributed to its standardized sequencing segment of the mitochondrial cytochrome c oxidase-1 gene (CO1) which has the necessary universality and variability making it a generally acceptable barcode region. CO1 is a haploid single locus that is uniparentally-inherited. Protein-coding regions are present in high-copy numbers making it an ideal barcode. The mitochondrial oxidase subunit I (COI) gene is a robust barcode with a suitable threshold for delineating animals and is not subject to drastic length variation, frequent mononucleotide repeats or microinversions. However, a low nucleotide substitution rate of plant mitochondrial genome [mtDNA] precludes the use of CO1 as a universal plant DNA barcode and makes the search for alternative barcode regions necessary. Currently, there exists no universal barcode for plants. The plastid region reveals leading candidate loci as appropriate DNA barcodes yet to be explored in biodiversity studies in Kenya. Four of these plastid regions are portions of coding genes (matK, rbcL, rpoB, and rpoC1), and three noncoding spacers (atpF-atpH, trnH-psbA, and psbK-psbL) which emerge as ideal candidate DNA loci. While different research groups propose various combinations of these loci, there exists no consensus;the lack thereof impedes progress in getting a suitable universal DNA barcode. Little research has attempted to investigate and document the applicability and extend of effectiveness of different DNA regions as barcodes to delineate cowpea at subspecies level. In this study we sought to test feasibility of the seven putative candidate DNA loci singly and in combination in order to establish a suitable single and multi-locus barcode regions that can have universal application in delineating diverse phylogeographic groups of closely related Kenyan cowpea variants. In this study, our focus was based on genetic parameters including analyses of intra- and infra-specific genetic divergence based on intra- and infra-specific K2P distances;calculation of Wilcoxon signed rank tests of intra-specific divergence among loci and coalescence analyses to delineate independent genetic clusters. Knowledge of DNA candidate loci that are informative will reveal the suitability of DNA barcoding as a tool in biodiversity studies. Results of this study indicate that: matK, trnH-psbA, psbK-psbL, and rbcL are good barcodes for delineating intra and infraspecific distances at single loci level. However, among the combinations, matK + trnH-psbA, rpoB + atpF-atpH + matK are the best barcodes in delineating cowpea subvariants. rbcL gene can be a suitable barcode marker at single locus level, but overall, multi locus approach appears more informative than single locus approach. The present study hopes to immensely contribute to the scanty body of knowledge on the novelty of DNA barcoding in cataloguing closely related cowpea variants at molecular level and hopes to open up future research on genomics and the possibility of use of conserved regions within DNA in inferring phylogenetic relationships among Kenyan cowpea variants.
文摘The desert plant Rhazya stricta has anticancer and antimicrobial properties, and is widely used in indigenous medicines of Saudi Arabia. However, the therapeutic benefits rely on an accurate identification of this species. The authenticity of R. stricta and other medicinal plants and herbs procured from local markets can be questionable due to a lack of clear phenotypic traits. DNA barcoding is an emerging technology for rapid and accurate species identification. In this study, six candidate chloroplastid barcodes were investigated for the authentication of R. stricta. We compared the DNA sequences from fifty locally collected and five market samples of R. stricta with database sequences of R. stricta and seven closely related species. We found that the coding regions matK, rbcL, rpoB, and rpoC1 were highly similar among the taxa. By contrast, the intergenic spacers psbK-psbI and atpF-atpH were variable loci distinct for the medicinal plant R. stricta. psbK-psbI clearly discriminated R. stricta samples as an efficient single locus marker, whereas a two-locus marker combination comprising psbK-psbI + atpF-atpH was also promising according to results from the Basic Local Alignment Search Tool and a maximum likelihood gene tree generated using PHyML. Two-dimensional DNA barcodes (i.e., QR codes) for the psbK-psbI and psbK-psbI + atpF-atpH regions were created for the validation of fresh or dried R. stricta samples.
基金Supported by Key Program for Sci-tech Plan of Hunan Province Science and Technology Department(2014SK2001)Sci-tech Project for Food and Drug Safety of Hunan Food and Drug Administration(Xiang Shi Yao Ke R201612)
文摘[Objectives] To identify ITS2 barcode of Lablab Semen Album and its adulterants,and provide a new method for the identification of Lablab Semen Album. [Methods] The ITS2 sequence was amplified by PCR and sequenced bi-directionally. After splicing by Codon Code Aligner,the data were processed with the aid MEGA software to construct the cluster dendrogram( neighbor-joining,NJ tree). [Results]The ITS2 sequence of Lablab Semen Album had length of 218 bp; the constructed cluster dendrogram indicated that all species were monophyletic and could be distinguished from other species. [Conclusions] The ITS2 barcode can be used for rapid identification of Lablab Semen Album and its adulterants and this experiment further verified that DNA barcode technology is effective in identification of traditional Chinese medicines.
文摘Because of its importance as a food source, Nemipterus japonicus(Bloch, 1791)(Nemipteridae) or Japanese threadfin bream is the best studied of these taxa, and numerous investigations have examined its fisheries, its biology and biochemistry. Despite such intensive work, the taxonomic status of N. japonicus has never been seriously questioned and it is regarded as a common species, widely distributed throughout the Indo-Western Pacific Ocean. In fact, Bloch's description of the type specimen of N. japonicus has ambiguous collection data and lacks a designation for the type locality, though it is probably Java. In this paper, DNA barcode results based on COI gene support the existence of two geographically separated lineages of the Japanese threadfin bream, both being an Indian Ocean and western Pacific lineage, with 2.7% sequence divergence, and the results indicate a possible existing of some cryptic species. The two lineages also possess a diagnostic difference in their belly color, with specimens in the South China Sea having a silver belly, while those from the Indian Ocean isolate specimen have a yellow coloration. Based upon new collections from the South China Sea, this species from the western Pacific is morphologically redescribed and its details of DNA barcode diversity are shown for the future investigations.
基金supported by the Beijing Natural Science Foundation(No.5212011)the National Natural Science Foundation of China(Nos.32170448,32130012)+1 种基金the 2115 Talent Development Program of China Agricultural Universitythe National Animal Collection Resource Center,China.
文摘Chrysopidae are a family of Neuroptera of significant importance in biocontrol against agricultural pests because of their predatory larvae.Currently,the taxonomy of Chrysopidae lacks a comprehensive revision,which impedes the exploration of species diversity as well as the selection and the conservation of green lacewings as biocontrol agents.We have established a DNA barcode reference library of the Chinese green lacewings based on an approximately complete sampling(95.63%)in 25 of the 34 provincial regions in China,comprising 1119 barcodes of 25 genera and 197 species(representing 85%genera and 43.62%species from China).Combining other 1049 high quality green lacewing DNA barcodes,we first inferred the optimal threshold of interspecific genetic divergence(1.87%)for successful species identification in multiple simulated scenarios based on present data.We further inferred the threshold of genetic divergence(7.77%)among genera with biocontrol significance.The inference and performance of the threshold appears to be mainly associated with the completeness of sampling,the proportion of closely related species,and the analytical approaches.Six new combinations,Apertochrysa platypa(Yang&Yang,1991)comb.nov.,Apertochrysa shennongana(Yang&Wang,1990)comb.nov.,Apertochrysa pictifacialis(Yang,1988)comb.nov.,Apertochrysa helana(Yang,1993)comb.nov.,Plesiochrysa rosulata(Yang&Yang,2002)comb.nov.,and Signochrysa hainana(Yang&Yang,1991),are proposed according to integrative species delimitation.Our library and optimal threshold will effectively facilitate the exploration of species diversity of green lacewings.Our study also provides a methodological reference in molecular delimitation of other insects.
