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1.
Sixty‐one Hawaiian algal specimens corresponding to members of the tribe Amansieae (Amansia and Osmundaria) were compared through DNA sequence analysis. Short DNA barcode‐like sequences of mitochondrial cytochrome c oxidase subunit I (COI) and universal plastid amplicon (UPA) markers were obtained for as many of the specimens as possible, and a subset of specimens was also used for amplification and sequencing of the nuclear small‐subunit rRNA (SSU) gene for phylogenetic inference in a broader taxonomic context. Statistical parsimony analysis of the COI and UPA markers for A. glomerata produced relationships among the samples that were largely congruent with each other, although the UPA marker was more conserved. The COI marker yielded three lineages, and nucleotide divergences for these three lineages were intermediate to those typically reported for intraspecific and interspecific comparisons, suggesting that they represent either incipient species or a complex of closely related species. The COI and UPA sequences demonstrated little to no divergence for Osmundaria obtusiloba and the taxon referred to as Amansia fimbrifolia. In contrast, specimens identified as A. daemelii were identical in sequence to lineage 3 sequences of A. glomerata, and it is recommended that this taxon no longer be included in species lists for the Hawaiian flora. Phylogenetic reconstruction based on the SSU gene was largely unresolved, indicating that this marker may be of limited utility for this purpose in this group of algae, but a small amount of nucleotide variation was found for samples of A. glomerata.  相似文献   

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A cladistic analysis of embiopterans, based on 157 species (representing 70% of the known genera) and 186 morphological characters, is presented, as well as a molecular analysis for 22 taxa using genes encoding 16S, 18S and 28S rDNA and COI. Species of all known families are included, except Andesembiidae Ross (specimens of which are in a private collection). The evidence presented supports the monophyly of four of the families (Australembiidae, Oligotomidae, Teratembiidae, and Anisembiidae). Notoligotomidae is paraphyletic and included within the Afro‐neotropical family Archembiidae (which is also paraphyletic). The genera Embia, Cleomia, Macrembia, and Dihybocercus (Embiidae) form, together with Australembiidae, a group strongly supported by morphology; the position of the remaining genera of Embiidae has two quite different resolutions. Almost 80% of the genera of Anisembiidae recently described appear as either paraphyletic or polyphyletic. Contrary to the opinion of other specialists, the major groups as well as the monophyly of some families are supported by features which have been ignored in classical approaches to the systematics of Embioptera, such as the ovipositor and cephalic and leg structures, characters with an almost perfect fit.  相似文献   

4.
The susceptibility of the dusky wireworm, Agriotes obscurus (L.) (Coleoptera: Elateridae), to different species and strains of entomopathogenic nematodes was tested in a virulence assay in the laboratory. Larvae were exposed to different nematode doses of 50 and 100 IJs/cm2. At a dose of 50 IJs/cm2, only a commercial strain Heterorhabditis bacteriophora Poinar and the native strain Steinernema carpocapsae (Weiser) B14 caused increased mortality compared with the control (11.1% and 13.3% mortality, respectively). At the higher dose tested, all strains (except Steinernema sp. D122) were virulent to A. obscurus larvae. Steinernema carpocapsae B14 caused higher mortality of wireworm (75.6%) and was used for the assay conducted in cages, with a dose of 100 IJs/cm2, in field conditions. The results showed that S. carpocapsae B14 controlled 48.3% of A. obscurus larvae, demonstrating that some entomopathogenic nematodes have the potential to control larvae of A. obscurus. However, further work is needed to improve their efficacy.  相似文献   

5.
Aim We investigated patterns of genetic diversity among invasive populations of Ampithoe valida and Jassa marmorata from the Pacific North American coast to assess the accuracy of morphological identification and determine whether or not cryptic diversity and multiple introductions contribute to the contemporary distribution of these species in the region. Location Native range: Atlantic North American coast; Invaded range: Pacific North American coast. Methods We assessed indices of genetic diversity based on DNA sequence data from the mitochondrial cytochrome c oxidase subunit I (COI) gene, determined the distribution of COI haplotypes among populations in both the invasive and putative native ranges of A. valida and J. marmorata and reconstructed phylogenetic relationships among COI haplotypes using both maximum parsimony and Bayesian approaches. Results Phylogenetic inference indicates that inaccurate species‐level identifications by morphological criteria are common among Jassa specimens. In addition, our data reveal the presence of three well supported but previously unrecognized clades of A. valida among specimens in the north‐eastern Pacific. Different species of Jassa and different genetic lineages of Ampithoe exhibit striking disparity in geographic distribution across the region as well as substantial differences in genetic diversity indices. Main conclusions Molecular genetic methods greatly improve the accuracy and resolution of identifications for invasive benthic marine amphipods at the species level and below. Our data suggest that multiple cryptic introductions of Ampithoe have occurred in the north‐eastern Pacific and highlight uncertainty regarding the origin and invasion histories of both Jassa and Ampithoe species. Additional morphological and genetic analyses are necessary to clarify the taxonomy and native biogeography of both amphipod genera.  相似文献   

6.
Genomic DNA samples from larvae of the beet webworm Loxostege sticticalis collected in the south‐western Russia were used to amplify mitochondrial cytochrome oxidase unit I (COI) gene. In a small proportion of samples, the sequenced product showed considerable heterogeneity due to admixture of a minor sequence. A preliminary BLAST analysis of a 100‐bp‐long fragment of this minor sequence showed its maximal similarity to the COI gene region of Cotesia, a genus of braconid larval endoparasitoids of Lepidoptera. An additional primer was designed to specifically amplify ca 300 bp of the COI gene region from Braconidae. As many as seven of 25 samples were positive by PCR. Sequencing of the amplified products in all these samples showed nucleotide sequence identity to the COI region of Cotesia vestalis (Cotesia plutellae) and the presence of two molecular haplotypes among individual parasitoid samples.  相似文献   

7.
The present study examines the population genetic structure of fifty‐nine specimens of Glis glis (Linneaus, 1766) from thirteen localities in central Europe, sequencing a 400‐bp segment of the mitochondrial cytochrome b (cyt b) gene and a 673‐bp segment of the cytochrome c oxidase subunit I (COI) gene. The consensus tree obtained from Bayesian analysis revealed a robust dichotomy, showing two sister groups: one clade includes samples from a wide geographical area, extending from north‐central Europe to northern Italy (major branch sensu Bilton), and the other comprises samples collected in central and southern Italy and in Sicily (Italian branch). According to the Tajima–Nei model, the two phylogroups were separated by a sequence divergence of 0.8% (cyt b) – 2.6% (COI), showing the COI gene to be more informative than cyt b. On a smaller geographical scale, the Italian clade was further substructured, displaying geographical differentiation along the Peninsula. The gene pool in this area was patchy; whereas populations from Sicily Island demonstrated fixed cyt b and COI haplotypes, assuming processes of isolation and selection. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 11–21.  相似文献   

8.
Accurate species-level identifications underpin many aspects of basic and applied biology;however,identifications can be hampered by a lack of discriminating morphological characters,taxonomic expertise or time.Molecular approaches,such as DNA"barcoding"of the cytochrome c oxidase(COI)gene,are argued to overcome these issues.However,nuclear encoding of mitochondrial genes(numts)and poor amplification success of suboptimally preserved specimens can lead to erroneous identifications.One insect group for which these molecular and morphological problems are significant are the dacine fruit flies(Diptera:Tephritidae:Dacini).We addressed these issues associated with COI barcoding in the dacines by first assessing several"universal"COI primers against public mitochondrial genome and numt sequences for dacine taxa.We then modified a set of four primers that more closely matched true dacine COI sequence and amplified two overlapping portions of the COI barcode region.Our new primers were tested alongside universal primers on a selection of dacine species,including both fresh preserved and decades-old dry specimens.Additionally,Bactrocera tiyoni mitochondrial and nuclear genomes were compared to identify putative numts.Four numt clades were identified,three of which were amplified using existing universal primers.In contrast,our new primers preferentially amplified the"true"mitochondrial COI barcode in all dacine species tested.The new primers also successfully amplified partial barcodes from dry specimens for which full length barcodes were unobtainable.Thus we recommend these new primers be incorporated into the suites of primers used by diagnosticians and quarantine labs for the accurate identification of dacine species.  相似文献   

9.
There are nine named species of buckeye butterflies (genus Junonia Hübner) in the Western Hemisphere. There is considerable geographic variation within Junonia species, and possible ongoing hybridization between species, suggesting that Junonia may be a ring species, but also making this a very difficult group to define taxonomically. We tried to determine whether two forms of Junonia from Argentina – conventionally referred to as Junonia genoveva hilaris C. & R. Felder, the light buckeye butterfly, and Junonia evarete flirtea (Fabricius), the dark buckeye butterfly – were genetically distinct species or simply colour forms of a single species using morphological characters, mitochondrial cytochrome oxidase I (COI) DNA barcodes, nuclear wingless (wg) locus DNA sequences, and anonymous nuclear Randomly Amplified Fingerprints (RAF). Phylogenetic analysis of COI identified two distinct mitochondrial haplotypes that differ by about 4% sequence divergence; one confined to light‐coloured Junonia specimens and one shared between some light‐coloured Junonia and all of dark‐coloured Junonia specimens. Analysis of nuclear wingless sequences revealed 32 alleles among 22 Junonia specimens and showed significant genetic differentiation between light‐coloured and dark‐coloured Junonia. Analysis of RAF genotypes suggests that there are actually three genetically distinct Junonia populations in Argentina: two with light wing coloration, and one with dark wing coloration. Genetic evidence of recent hybridization among these populations was also observed, consistent with the ring species hypothesis. Careful comparisons of morphological characters between Argentinian Junonia and Junonia species from elsewhere in South America suggests that the two light‐coloured populations correspond to J. genoveva and either a genetically disparate population of the same species or an undescribed cryptic Junonia species, The dark‐coloured population may correspond to J. wahlbergi Brévignon. Our data suggest that COI DNA barcodes by themselves are not very useful for studying Junonia taxonomy, population structure or evolution.  相似文献   

10.
Martin Pckert 《Ibis》2022,164(1):336-342
Online repositories of DNA sequences are a rich and indispensable source of comparative data for biodiversity research and taxonomic studies. Despite increasingly high data quality of published sequences and associated metadata, particular attention should be paid to taxonomic assignment of DNA sequences, in particular if voucher specimens are not available or cannot be examined. In this study, two nearly identical mitogenomes of two distinctive plover species (Charadrius alexandrinus and Charadrius placidus) were re-analysed and compared with a comprehensive dataset of DNA-barcode sequences (cytochrome-oxidase subunit 1, COI) for 55 shorebird species. Phylogenetic analysis separated the two plover species into two reciprocally monophyletic clades that differed by mean p-distances of 11.5–14.7%; however, the COI sequence from the C. placidus mitogenome was nested in the Kentish Plover clade (C. alexandrinus). A similar mismatch was found for another DNA-barcode sequence from a Charadrius mongolus mitogenome that clustered with one of two clades of Charadrius leschenaultii in the COI tree. These results strongly suggest that, to date, two of seven mitogenomes published for Charadriidae are not representative of the taxon names to which the respective GenBank entries were assigned. Only a few DNA-barcode sequences were associated with outdated taxonomy, while others were suspected to be chimeric sequences. Thus, free access to digital sequence information is a key factor for steady improvement of data quality in online repositories via swarm intelligence of the scientific community.  相似文献   

11.
We tested the efficiency of cytochrome oxidase I (COI)‐barcoding as a taxonomic tool to discriminate and identify sympatric shrew species on Mount Nimba (Guinea). We identified 148 specimens at the species level using morphological characters and comparison with type specimens, including several taxa from Mount Nimba. We identified ten morphospecies and tested aspects of genetic diversity and monophyly using genetic data from three mitochondrial (16S, cytochrome b, and COI) and one nuclear marker (the breast cancer gene, BRCA). Nine morphospecies were validated under the phylogenetic and genetic species concepts, including the recently diverged species Crocidura buettikoferi, Crocidura theresae, and Crocidura grandiceps. Under the same concepts, our analyses revealed the presence of two cryptic species amongst animals identified as Crocidura muricauda. We then tested the efficiency of barcoding thanks to commonly used phenetic methods, with the 148 specimens representing 11 potentially valid species based on morphological and molecular data. We show that COI‐barcoding is a powerful tool for shrew identification and can be used for taxonomic surveys. The comparison of genetic divergence values shows the presence of a barcoding gap (i.e. difference between the highest intraspecific and the lowest interspecific genetic divergence values). Given that only a few COI sequences are available for Afrotropical shrews, our work is an important step forward toward their enrichment. We also tested the efficiency of the three other sequenced markers and found that cytochrome b is as efficient as COI for barcoding shrews. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 672–687.  相似文献   

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Barilius bendelisis and Barilius vagra inhabit mostly in the spring‐fed streams of Indian Himalaya and constitute an important portion of protein diet of the rural human population residing near the stream banks. In spite of large aquaculture importance of this genus very less morphometric and molecular studies have been conducted. This study addresses morphometric and molecular characterization of B. bendelisis and B. vagra by using truss analysis and mitochondrial COI gene. A total of 293 samples of Barilius bendelisis and 127 samples of Barilius vagra were collected from three different sites of Chenab river basin from March 2015 to April 2017. 14 landmarks were used to measure 90 truss measurements from digital images of specimens using network of three softwares, tpsUtil, tpsDig2 and PAST. A total of 89 distance variables exhibited significant differences among the populations. The principal component analysis generated ten components explaining 89.164% of total variance among six populations of B. bendelisis and B. vagra. 89.0% of individuals of B. bendelisis and B. vagra were classified into their original groups. The Phylogenetic analysis with other published COI sequences revealed distinct nature of these two species. The study may aid in taxonomic identification and phenotypic divergence which will be helpful in proper conservation and management of these species of hill trout in India.  相似文献   

14.
The Tetraodontidae family are known to have relatively small and compact genomes compared to other vertebrates. The obscure puffer fish Takifugu obscurus is an anadromous species that migrates to freshwater from the sea for spawning. Thus the euryhaline characteristics of T. obscurus have been investigated to gain understanding of their survival ability, osmoregulation, and other homeostatic mechanisms in both freshwater and seawater. In this study, a high quality chromosome‐level reference genome for T. obscurus was constructed using long‐read Pacific Biosciences (PacBio) Sequel sequencing and a Hi‐C‐based chromatin contact map platform. The final genome assembly of T. obscurus is 381 Mb, with a contig N50 length of 3,296 kb and longest length of 10.7 Mb, from a total of 62 Gb of raw reads generated using single‐molecule real‐time sequencing technology from a PacBio Sequel platform. The PacBio data were further clustered into chromosome‐scale scaffolds using a Hi‐C approach, resulting in a 373 Mb genome assembly with a contig N50 length of 15.2 Mb and and longest length of 28 Mb. When we directly compared the 22 longest scaffolds of T. obscurus to the 22 chromosomes of the tiger puffer Takifugu rubripes, a clear one‐to‐one orthologous relationship was observed between the two species, supporting the chromosome‐level assembly of T. obscurus. This genome assembly can serve as a valuable genetic resource for exploring fugu‐specific compact genome characteristics, and will provide essential genomic information for understanding molecular adaptations to salinity fluctuations and the evolution of osmoregulatory mechanisms.  相似文献   

15.
Although tomato psyllid, Bactericera cockerelli (Sulc) (Homoptera, Psyllidae), annually causes significant losses in potato and tomato crops in eastern Mexico and the central United States, infestations in western North America have been historically rare. However, substantial populations appeared in 2001 in western North America and caused losses in tomato production exceeding 80%; losses in 2004 reached 50%. To determine if these new outbreaks were the result of a simple range expansion or the evolution of a new B. cockerelli biotype, inter simple sequence repeat (ISSR) markers, as well as mitochondrial gene cytochrome oxidase I (COI), internal transcribed spacer 2 (ITS2), and wsp sequence data were used to characterize populations of the psyllid. Western populations from Baja, Mexico, Orange County, and Ventura County were compared with populations from central USA (Colorado and Nebraska) and eastern Mexico (Coahuila). Based on ISSR markers, the psyllid populations clustered into two groups, with one group including populations from western North America and the other group including populations from central USA and eastern Mexico. For COI comparisons, there was one base‐pair difference found in the 544 bp‐long COI fragments, but the populations again segregated along the same geographic lines. Two strains of Wolbachia were identified, the maximal differences between wsp clones from all populations was 5 bp for strain Bac1 and 23 bp for strain Bac2 out of a 555‐bp fragment. The ISSR data, therefore, were consistent in indicating the development of a new psyllid biotype that has adapted to western North America rather than a simple range expansion, but the other genetic data sets were less conclusive.  相似文献   

16.
During exploratory surveys in the tributaries (Penganga and Satnala) of Godavari and (Bheema) Krishna basins, specimens of mahseer were collected. The morpho‐meristic characteristics of these specimens conformed to the taxonomic keys for Tor tor. The mitochondrial COI sequences of these specimens clustered with the T. tor specimens from the River Narmada and were distinct from the other mahseer such as T. khudree and T. mussullah, which are known to exist in the rivers of the region. This confirmed the distribution of T. tor in the rivers of peninsular India and indicated an extended distribution of the known range. The major predominating habitat characteristics of collection areas were cobbles mixed with gravel, and a riparian cover of shrubs and trees. The occurrence of fingerling size specimens in the river suggests that the species has adapted and is likely to have established self‐recruiting populations in these rivers.  相似文献   

17.
Ants in the Neotropical genus Sericomyrmex Mayr cultivate fungi for food. Both ants and fungi are obligate, coevolved symbionts. The taxonomy of Sericomyrmex is problematic because the morphology of the worker caste is generally homogeneous across all of the species within the genus, species limits are vague, and the relationships between them are unknown. We used ultraconserved elements (UCEs) as genome‐scale markers to reconstruct evolutionary history and to infer species boundaries in Sericomyrmex. We recovered an average of ~990 UCE loci for 88 Sericomyrmex samples from across the geographical range of the genus as well as for five outgroup taxa. Using maximum likelihood and species‐tree approaches, we recovered nearly identical topologies across datasets with 50–95% matrix completeness. We identify nine species‐level lineages in Sericomyrmex, including two new species. This is less than the previously described 19 species, even accounting for two species for which we had no UCE samples, which brings the total number of Sericomyrmex species to 11. Divergence‐dating analyses recovered 4.3 Ma as the crown‐group age estimates for Sericomyrmex, indicating a recent, rapid radiation. We also sequenced mitochondrial cytochrome oxidase subunit I (COI) for 125 specimens. Resolution and support for clades in our COI phylogeny are weak, indicating that COI is not an appropriate species‐delimitation tool. However, taxa within species consistently cluster together, suggesting that COI is useful as a species identification (‘DNA barcoding’) tool. We also sequenced internal transcribed spacer (ITS) and large subunit (LSU) for 32 Sericomyrmex fungal cultivars. The fungal phylogeny confirms that Sericomyrmex fungi are generalized higher‐attine cultivars, interspersed with Trachymyrmex‐associated fungal species, indicating cultivar sharing and horizontal transfer between these two genera. Our results indicate that UCEs offer immense potential for delimiting and resolving relationships of problematic, recently diverged species.  相似文献   

18.
Little is known about the natural enemies of wireworms (Coleoptera: Elateridae), but there are frequent anecdotal reports of (usually unnamed) stiletto fly larvae (Diptera: Therevidae) preying on various species. We observed larvae of Thereva nobilitata (Fabricius) feeding on larvae of the dusky wireworm, Agriotes obscurus L., during the summer of 2011, in Agassiz, British Columbia. This finding is of interest as: both the predator and the wireworm are introduced species to this area from Europe; T. nobilitata is uncommon in North America; and this predator has not been associated with any wireworm species previously. We observed that larvae of male and female T. nobilitata will feed on various sizes of A. obscurus larvae, most feeding being carried out by the smallest T. nobilitata larvae. These findings suggest future work should assess the potential for therevid larvae as top‐down regulators of Agriotes larvae under field conditions.  相似文献   

19.
Taxonomic identification can be difficult when two or more species appear morphologically similar. DNA barcoding based on the sequence of the mitochondrial cytochrome c oxidase 1 gene (COI) is now widely used in identifying animal species. High‐resolution melting analysis (HRM) provides an alternative method for detecting sequence variations among amplicons without having to perform DNA sequencing. The purpose of this study was to determine whether HRM of the COI barcode can be used to distinguish animal species. Using anurans as a model, we found distinct COI melting profiles among three congeners of both Lithobates spp. and Hyla spp. Sequence variations within species shifted the melting temperature of one or more melting domains slightly but do not affect the distinctness of the melting profiles for each species. An NMDS ordination plot comparing melting peak profiles among eight Anuran species showed overlapping profiles for Lithobates sphenocephala and Gastrophryne carolinensis. The COI amplicon for both species contained two melting domains with melting temperatures that were similar between the two species. The two species belong to two different families, highlighting the fact that COI melting profiles do not reveal phylogenetic relationships but simply reflect DNA sequence differences among stretches of DNA within amplicons. This study suggests that high‐resolution melting analysis of COI barcodes (COI‐HRM) may be useful as a simple and rapid method to distinguish animal species that appear morphologically similar.  相似文献   

20.
Lungworms from the genus Rhabdias are common parasites of amphibians and reptiles distributed worldwide. To assess the diversity of Rhabdias spp., we performed molecular analyses of 35 specimens sampled in different regions of Brazil. Molecular analyses were based on the internal transcribed spacer (ITS), large subunit (28S) ribosomal and the cytochrome oxidase I (COI) mitochondrial genes. DNA sequence divergence was compared among ribosomal and mitochondrial genes, analyses using the general mixed Yule‐coalescent (GMYC) method based on the COI gene were used to identify possible cryptic diversity, and phylogenetic analyses using concatenated ITS and 28S ribosomal genes were used to test the monophyly of Rhabdiasidae. We revealed five morphospecies: R. cf. stenocephala, R. breviensis, R. pseudosphaerocephala and two new species, Rhabdias sp.4 and Rhabdias sp.5. DNA sequence levels of divergence among genes ITS, 28S and COI were compared, and the efficiency of the molecular markers to identify species (ITS and COI) and lineages (COI) was tested. GMYC was assigned to 17 well‐supported clades (i.e., 17 species), and cryptic diversity was detected in the Neotropical region as evidenced by the multiple lineages in R. breviensis and R. pseudosphaerocephala. In addition, our results suggest evidence for host–parasite cophylogeny in the R. pseudosphaerocephala complex and dispersal events among their populations. Phylogenetic analyses supported the monophyly of Rhabdiasidae and improved the resolution of main clades. Rhabdias breviensis is closely related to Rhabdias cf. africanus, Rhabdias cf. stenocephala, R. pseudosphaerocephala, Rhabdias sp.4 and Rhabdias sp.5 grouping together in a main clade with Neotropical‐related species. The large geographical distribution appeared to be a phylogenetic pattern among the species of Rhabdias from the neotropics.  相似文献   

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