The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications — TEI-tagged view

Rolf Henrik Nilsson, Karl-Henrik Larsson, Andy F. S. Taylor, Johan Bengtsson‐Palme, Thomas Stjernegaard Jeppesen, Dmitry Schigel, Peter G. Kennedy, Kathryn T. Picard, Frank Oliver Glöckner, Leho Tedersoo, Irja Saar, Urmas Kõljalg, Kessy Abarenkov · 2018 · agricultural-and-biological-sciences · doi:10.1093/nar/gky1022 · full text at the source · TEI xml · tagged edition · index · concepts · authors
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UNITE system-or-tool-building173

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2018<date>A year or date.

Rolf Henrik NilssonpersName, Karl-Henrik LarssonpersName, Andy F. S. TaylorpersName, Johan Bengtsson‐PalmepersName, Thomas Stjernegaard JeppesenpersName, Dmitry SchigelpersName, Peter G. KennedypersName, Kathryn T. PicardpersName, Frank Oliver GlöcknerpersName, Leho TedersoopersName, Irja SaarpersName, Urmas KõljalgpersName, Kessy AbarenkovpersName (2018date). “The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications.” Nucleic Acids Researchtitle·j.

Object of study —

Research question —

Contribution —

Cross-disciplinary analysis
content-tags & facets: phenomenon · claim-type · cross-domain-transfer · mechanism · claim-relation · replication-status · limitation — grounded in the full text
phenomenonmolecular identification of fungi from public ITS barcode sequences — “UNITE ( https://unite.ut.ee/ ) is a web-based database and sequence management environment for the molecular identification of fungi. It targets the formal fungal barcode—the nuclear ribosomal internal transcribed spacer (ITS) region—and offers all ∼1 000 000 public fungal ITS sequences for reference.”
claim-typemethod — “Recent improvements include redesigned handling of unclassifiable species hypotheses, integration with the taxonomic backbone of the Global Biodiversity Information Facility, and support for an unlimited number of parallel taxonomic classification systems.”
mechanismWe hope and expect that extending the mapping of biodiversity into the molecular realm will lead to richer and unbiased biodiversity evidence to positively impact global modelling and decision-making. — “We hope and expect that extending the mapping of biodiversity into the molecular realm will lead to richer and unbiased biodiversity evidence to positively impact global modelling and decision-making.”mechanisms[0]
senseUNITE - a web-based database and sequence-management environment for molecular identification of fungi — “Abstract UNITE ( https://unite.ut.ee/ ) is a web-based database and sequence management environment for the molecular identification of fungi.”senses[0]
Content tags
content-observations: finding · quantity · variable · definition · key-term — grounded in the full text
findingIn-house and web-based third-party sequence curation and annotation have resulted in more than 275 000 improvements to the data over the past 15 years. — “In-house and web-based third-party sequence curation and annotation have resulted in more than 275 000 improvements to the data over the past 15 years.”content_tags.findings[0]
finding( G ) Information on ecology (interacting taxa) if associated with the individual sequences. — “( G ) Information on ecology (interacting taxa) if associated with the individual sequences.”content_tags.findings[1]
finding‘RefSeq’ indicates that the sequence was selected manually to be the representative sequence for the SHs. — “‘RefSeq’ indicates that the sequence was selected manually to be the representative sequence for the SHs.”content_tags.findings[2]
findingImproved UNITE-SILVA collaboration would offer both robust phylogenetic placement and unambiguous communicability at the species level, a much sought-after combination ( 33 ). — “Improved UNITE-SILVA collaboration would offer both robust phylogenetic placement and unambiguous communicability at the species level, a much sought-after combination ( 33 ).”content_tags.findings[3]
findingThese are clustered into ∼459 000 species hypotheses and assigned digital object identifiers (DOIs) to promote unambiguous reference across studies. — “These are clustered into ∼459 000 species hypotheses and assigned digital object identifiers (DOIs) to promote unambiguous reference across studies.”content_tags.findings[4]
findingRecent improvements include redesigned handling of unclassifiable species hypotheses, integration with the taxonomic backbone of the Global Biodiversity Information Facility, and support for an unlimited number of parallel taxonomic classification systems. — “Recent improvements include redesigned handling of unclassifiable species hypotheses, integration with the taxonomic backbone of the Global Biodiversity Information Facility, and support for an unlimited number of parallel taxonomic classification systems.”content_tags.findings[5]
findingINTRODUCTION The fungal kingdom comprises an estimated 2.2–3.8 million species of heterotrophic eukaryotes, most of which are inconspicuous and substrate-dwelling ( 1 ). — “INTRODUCTION The fungal kingdom comprises an estimated 2.2–3.8 million species of heterotrophic eukaryotes, most of which are inconspicuous and substrate-dwelling ( 1 ).”content_tags.findings[6]
findingMolecular (DNA sequence) data are routinely used to explore fungi and fungal communities through barcoding and metabarcoding efforts. — “Molecular (DNA sequence) data are routinely used to explore fungi and fungal communities through barcoding and metabarcoding efforts.”content_tags.findings[7]
findingUNITE seeks to provide reproducible identification of fungi and facilitate mycological progress by assembling and disseminating taxonomic, ecological, and geographical metadata for all fungi known from ITS sequence data. — “UNITE seeks to provide reproducible identification of fungi and facilitate mycological progress by assembling and disseminating taxonomic, ecological, and geographical metadata for all fungi known from ITS sequence data.”content_tags.findings[8]
findingAll such SHs (458 797 as of August 2018) are assigned a unique digital object identifier (DOI) to allow stable, unambiguous reference across studies, even in the complete absence of meaningful taxonomic names. — “All such SHs (458 797 as of August 2018) are assigned a unique digital object identifier (DOI) to allow stable, unambiguous reference across studies, even in the complete absence of meaningful taxonomic names.”content_tags.findings[9]
findingUsers can download the corresponding multiple sequence alignment files or compare newly generated sequences to the SHs through BLAST ( 7 ), the recently launched probabilistic assigner PROTAX ( 8 ), and other search and query functions. — “Users can download the corresponding multiple sequence alignment files or compare newly generated sequences to the SHs through BLAST ( 7 ), the recently launched probabilistic assigner PROTAX ( 8 ), and other search and query functions.”content_tags.findings[10]
findingUNITE supports web-based third-party annotation of sequence data to reflect recent nomenclatural and taxonomic changes and to correct the often-suboptimal state of taxonomic annotation and other metadata items among public DNA sequences. — “UNITE supports web-based third-party annotation of sequence data to reflect recent nomenclatural and taxonomic changes and to correct the often-suboptimal state of taxonomic annotation and other metadata items among public DNA sequences.”content_tags.findings[11]
findingParticipation in sequence annotation efforts is encouraged through organization of annotation jamborees targeting, e.g. plant pathogenic fungi ( 13 ) or the built mycobiome ( 14 ). — “Participation in sequence annotation efforts is encouraged through organization of annotation jamborees targeting, e.g. plant pathogenic fungi ( 13 ) or the built mycobiome ( 14 ).”content_tags.findings[12]
findingSuch a system is implemented together with a range of other quality-control measures to maintain a high quality standard for the entries in UNITE. — “Such a system is implemented together with a range of other quality-control measures to maintain a high quality standard for the entries in UNITE.”content_tags.findings[13]
findingSince then, mycology has undergone far-reaching changes in the wake of high-throughput sequencing (HTS) methods and the realisation that undescribed, ‘dark’ taxa permeate the fungal tree of life and may dominate the functional biodiversity of the planet. — “Since then, mycology has undergone far-reaching changes in the wake of high-throughput sequencing (HTS) methods and the realisation that undescribed, ‘dark’ taxa permeate the fungal tree of life and may dominate the functional biodiversity of the planet.”content_tags.findings[14]
findingChanges in nomenclatural rules and taxonomic principles have further fuelled the field ( 15 ). — “Changes in nomenclatural rules and taxonomic principles have further fuelled the field ( 15 ).”content_tags.findings[15]
findingIn this paper, we detail the recent changes we have implemented in UNITE to meet the challenges posed by technological and conceptual advances in the mycological and molecular ecology communities. — “In this paper, we detail the recent changes we have implemented in UNITE to meet the challenges posed by technological and conceptual advances in the mycological and molecular ecology communities.”content_tags.findings[16]
findingDATABASES Sequence data and quality control Public fungal ITS sequences are sourced from the INDSC and subjected to a range of quality control measures, including processing with ITSx ( 16 ) and UCHIME ( 17 ) in an attempt to reject non-ITS and chimeric sequences. — “DATABASES Sequence data and quality control Public fungal ITS sequences are sourced from the INDSC and subjected to a range of quality control measures, including processing with ITSx ( 16 ) and UCHIME ( 17 ) in an attempt to reject non-ITS and chimeric sequences.”content_tags.findings[17]
findingSubstandard entries are kept for future reference but are not used for identification purposes. — “Substandard entries are kept for future reference but are not used for identification purposes.”content_tags.findings[18]
findingSequences found to contain the full ITS2 subregion of the ITS region are clustered at 97–100% similarity in steps of 0.5% to produce SHs. — “Sequences found to contain the full ITS2 subregion of the ITS region are clustered at 97–100% similarity in steps of 0.5% to produce SHs.”content_tags.findings[19]
findingA representative sequence is chosen randomly from the most abundant sequence type in each SH, although this choice can be overridden manually to reflect, e.g. sequences derived from type material. — “A representative sequence is chosen randomly from the most abundant sequence type in each SH, although this choice can be overridden manually to reflect, e.g. sequences derived from type material.”content_tags.findings[20]
findingEfforts are under way to also include partial ITS sequences stemming from HTS studies in this system. — “Efforts are under way to also include partial ITS sequences stemming from HTS studies in this system.”content_tags.findings[21]
findingWe are currently working on adding ITS2-derived HTS studies to UNITE. — “We are currently working on adding ITS2-derived HTS studies to UNITE.”content_tags.findings[22]
findingWe have added a first set of long PacBio reads comprising the full ITS region and some 1000 bases of the LSU gene to UNITE and the species hypothesis system. — “We have added a first set of long PacBio reads comprising the full ITS region and some 1000 bases of the LSU gene to UNITE and the species hypothesis system.”content_tags.findings[23]
findingA history of all annotations is kept so that it is possible to track changes over time, e.g. in the names given to a sequence. — “A history of all annotations is kept so that it is possible to track changes over time, e.g. in the names given to a sequence.”content_tags.findings[24]
Concepts
terms this paper carries, each with the sentence it was cut from — the layer that joins one paper to another. Terms with no quote yet are on CONCEPTS.html.
conceptUNITE — “Abstract UNITE ( https://unite.ut.ee/ ) is a web-based database and sequence management environment for the molecular identification of fungi.”concepts[0]

Full text — tagged

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Abstract. Abstract UNITEterm·dom ( https://uniteterm·dom.ut.ee/ ) is a web-based database and sequence management environment for the molecular identification of fungi. It targets the formal fungal barcode—the nuclear ribosomal internal transcribed spacer (ITS) region—and offers all ∼1 000 000 public fungal ITS sequences for reference. These are clustered into ∼459 000 species hypotheses and assigned digital object identifiers (DOIs) to promote unambiguous reference across studies. In-house and web-based third-party sequence curation and annotation have resulted in more than 275 000 improvements to the data over the past 15 years. UNITEterm·dom serves as a data provider for a range of metabarcoding software pipelines and regularly exchanges data with all major fungal sequence databases and other community resources. Recent improvements include redesigned handling of unclassifiable species hypotheses, integration with the taxonomic backbone of the Global Biodiversity Information Facility, and support for an unlimited number of parallel taxonomic classification systems. INTRODUCTION The fungal kingdom comprises an estimated 2.2–3.8 million species of heterotrophic eukaryotes, most of which are inconspicuous and substrate-dwelling ( 1 ). Molecular (DNA sequence) data are routinely used to explore fungi and fungal communities through barcoding and metabarcoding efforts. The ∼600-base nuclear ribosomal internal transcribed spacer (ITS) region is the primary genetic marker for such pursuits ( 2 ), and more than 1 000 000 full-length, Sanger-derived fungal ITS sequences are available for reference in the International Nucleotide Sequence Databases Collaboration (INSDC; 3 ). Significant processing and annotation are necessary before the public sequences can be used for taxonomic annotation of newly generated sequence data, and the UNITEterm·dom database for molecular identification of fungi ( 4 ; https://uniteterm·dom.ut.ee/ ) was launched in 2003 as a curated copy of the public fungal ITS sequences. UNITEterm·dom seeks to provide reproducible identification of fungi and facilitate mycological progress by assembling and disseminating taxonomic, ecological, and geographical metadata for all fungi known from ITS sequence data. Fungal metabarcoding struggles with very large numbers of operational taxonomic units (OTUs; 5 ) that cannot be identified to any meaningful taxonomic lineage beyond, e.g. the kingdom or phylum level ( 6 ). UNITEterm·dom regularly clusters all ITS sequences at several sequence similarity thresholds to obtain approximate species-level OTUs referred to as species hypotheses (SHs). All such SHs (458 797 as of August 2018) are assigned a unique digital object identifier (DOI) to allow stable, unambiguous reference across studies, even in the complete absence of meaningful taxonomic names. A designated URL (e.g. https://uniteterm·dom.ut.ee/bl_forw_sh.php?sh_name=SH181628.07FU ) where all pertinent metadata are displayed is available for all SHs. Users can download the corresponding multiple sequence alignment files or compare newly generated sequences to the SHs through BLAST ( 7 ), the recently launched probabilistic assigner PROTAX ( 8 ), and other search and query functions. In addition, compatible datasets assembled from the SHs are provided for a range of metabarcoding software pipelines and other resources ( https://uniteterm·dom.ut.ee/repository.php ), notably QIIME ( 9 ), MOTHUR ( 10 ), USEARCH ( 11 ) and micca ( 12 ). UNITEterm·dom supports web-based third-party annotation of sequence data to reflect recent nomenclatural and taxonomic changes and to correct the often-suboptimal state of taxonomic annotation and other metadata items among public DNA sequences. Participation in sequence annotation efforts is encouraged through organization of annotation jamborees targeting, e.g. plant pathogenic fungi ( 13 ) or the built mycobiome ( 14 ). Any changes contributed are credited through co-authorship of the underlying DOIs, with citations to all DOIs (SHs) being monitored by DataCite ( https://www.datacite.org/ ). The community-oriented nature of UNITEterm·dom encourages participation but also incorporates a need for a review-type procedure of handling user-provided annotations. Such a system is implemented together with a range of other quality-control measures to maintain a high quality standard for the entries in UNITEterm·dom. The year 2003 saw the first public release of UNITEterm·dom. Since then, mycology has undergone far-reaching changes in the wake of high-throughput sequencing (HTS) methods and the realisation that undescribed, ‘dark’ taxa permeate the fungal tree of life and may dominate the functional biodiversity of the planet. Changes in nomenclatural rules and taxonomic principles have further fuelled the field ( 15 ). In this paper, we detail the recent changes we have implemented in UNITEterm·dom to meet the challenges posed by technological and conceptual advances in the mycological and molecular ecology communities. DATABASES Sequence data and quality control Public fungal ITS sequences are sourced from the INDSC and subjected to a range of quality control measures, including processing with ITSx ( 16 ) and UCHIME ( 17 ) in an attempt to reject non-ITS and chimeric sequences. Substandard entries are kept for future reference but are not used for identification purposes. Sequences found to contain the full ITS2 subregion of the ITS region are clustered at 97–100% similarity in steps of 0.5% to produce SHs. A representative sequence is chosen randomly from the most abundant sequence type in each SH, although this choice can be overridden manually to reflect, e.g. sequences derived from type material. Efforts are under way to also include partial ITS sequences stemming from HTS studies in this system. The mind-boggling number of such sequences (>1 billion partial fungal ITS reads in Sequence Read Archive ( 18 , 19 )) coupled with the difficulties of associating non-overlapping datasets of ITS1 and ITS2 sequences impede progress. We are currently working on adding ITS2-derived HTS studies to UNITEterm·dom. In parallel, long HTS reads from technologies such as PacBIO ( https://www.pacb.com/ ) and Oxford Nanopore ( https://nanoporetech.com/ ) are gradually becoming available. We have added a first set of long PacBio reads comprising the full ITS region and some 1000 bases of the LSU gene to UNITEterm·dom and the species hypothesis system. Web-based third-party annotation of sequence entries covers most aspects of public sequences, including taxonomic name, country of collection, and substrate of collection. A history of all annotations is kept so that it is possible to track changes over time, e.g. in the names given to a sequence. This allows for competing views of taxonomic annotations to be expressed. As of fall 2018, a total of 276 889 third-party annotations have been provided by UNITEterm·dom users (including 101 833 additions of country of collection, 69 539 annotations of substrate of collection and 23 410 taxonomic re-annotations). UNITEterm·dom taxonomy By default, UNITEterm·dom uses the NCBI Taxonomy classification ( 20 ) as taxonomic backbone, supplemented with modifications from Index Fungorum ( http://www.indexfungorum.org ) and MycoBank ( 21 ). A breakdown of the SHs in terms of taxonomy and geography (August 2018) is provided in Table 1 . UNITEterm·dom has the ambition to offer all public fungal ITS sequences to the user, and these data are often complicated from a taxonomic point of view. Taxonomic misidentification is rife, as are sequences lacking meaningful taxonomic annotation in the first place (e.g. ‘Uncultured fungus’). SHs with sequences of conflicting taxonomic information are flagged for manual curation by curators or experienced users. Such trusted third-party users can rename sequences through their web browser. Sequences from type material (e.g. GenBank RefSeq Loci; 22 ) are used to inform the taxonomic annotation of similar sequences. For instance, an unnamed sequence that is at least 97% similar in a global ITS alignment to a fully annotated type-derived sequence can safely be annotated at the family and typically also at the genus levels. The original name as well as the history of re-annotations are kept for reference for all sequences. Table 1. A breakdown of the SHs in UNITEterm·dom (August 2018) in terms of taxonomy (following 23 ) and geography, using the 98.5% threshold level. Subkingdom Number of SHs (at 1.5% threshold) Dikarya (Basidiomycota + Ascomycota) 63 062 Unidentified 6071 Mucoromyceta 3711 Chytridiomyceta 502 Rozellomyceta 200 Zoopagomyceta 76 Blastocladiomyceta 42 Basidiobolomyceta 22 Olpidiomyceta 14 Aphelidiomyceta 5 GS01 2 Country Number of SHs (at 1.5% threshold) United States 13 802 China 7502 Canada 4191 Japan 3883 Germany 3667 Australia 3624 Spain 3065 Estonia 3047 Finland 3039 Sweden 2949 Most SHs comprise sequences from multiple countries, such that many SHs contributed to several countries in the geography list. The 10 countries with the largest number of SHs are shown. There is no generally agreed upon, up-to-date system for fungal classification, although a synthesis was recently published ( 23 ). Fungal classification is in a state of flux, and different, partly incompatible classification systems are used across mycological resources such as Index Fungorum ( http://www.indexfungorum.org ), MycoBank ( http://www.mycobank.org ) and the INDSC ( 24 ). To address the need to navigate across competing taxonomic systems, the new release of UNITEterm·dom allows representation of an arbitrary number of alternative taxonomic systems. For this we introduce the Taxon Hypothesis (TH) concept that allows communication of sequence-based SHs over many classifications at the same time. As with SHs, all THs will receive unique DOI-based stable identifiers, and single SHs can belong to different higher taxa in different classifications. The results of different studies are comparable and re-usable when TH DOIs are used for communication. The taxon hypothesis pages are due for launch late 2018. Database structure and adherence to metadata standards UNITEterm·dom is an assemblage of datasets managed on the PlutoF platform ( https://plutof.ut.ee/ ), which uses PostgreSQL ( https://www.postgresql.org/ ) and the PostGIS database engines as well as the Ember.js and DRF frameworks ( 25 ). PlutoF comprises nearly 200 tables and is modelled to allow exact, standards-compliant representation of DNA sequences and sequence metadata in terms of, e.g. taxonomy, nomenclature, ecology, and geography. For sequence data and metadata, the MIxS standard ( 26 ) is implemented. For the taxonomical, ecological, and other data types, a range of standards is used (e.g. DarwinCore, Ecological Metadata Language, and the Microbiological Common Language). The PlutoF platform is a part of the DataCite consortium, which allows UNITEterm·dom to publish SHs with DOIs. The PlutoF platform collaborates with the Global Biodiversity Information Facility (GBIF; https://www.gbif.org/ ), and sequence-based SHs from UNITEterm·dom are as of June 2018 part of the GBIF taxonomic backbone. This makes it possible to upload the results of metabarcoding studies directly into the GBIF database ( https://www.gbif.org/news/2LrgV5t3ZuGeU2WIymSEuk ) and have them scored as biological observations even if no formal scientific names are available for the underlying taxa. Datasets UNITEterm·dom core release The sequence data of UNITEterm·dom are available to the user in a number of interactive and static ways. Our non-redundant core release ( https://uniteterm·dom.ut.ee/repository.php ) comprises a representative sequence from each non-singleton SH and currently includes 458 797 SHs variously delimited at 97–100% similarity to reflect the species level as closely as possible in light of the differences in intraspecific ITS variability across the fungal tree of life ( 2 ). This release is provided in the FASTA format ( 27 ) for, e.g. local BLAST searches, as well as formats tailored for a range of metabarcoding software pipelines, including QIIME, MOTHUR and USEARCH. A generic FASTA release of all ∼1 000 000 sequences is also available. Experienced users will find additional variations of these files available, differing in whether singleton SHs are included or not, the way sequence trimming was carried out, and the way the taxonomic affiliation of the sequences is provided. All releases include taxonomic re-annotations, such that they differ significantly from the INSDC release of the same fungal ITS sequences. UNITEterm·dom auxiliary releases UNITEterm·dom provides a number of release datasets tailored to meet specific requests and needs of the scientific community ( https://uniteterm·dom.ut.ee/repository.php ). For example, the ‘top 50 most wanted species of fungi’ release comprises the largest SHs for which no meaningful taxonomic annotation at, e.g. the phylum level can be derived at present ( 6 ). Its purpose is to encourage the scientific community to clarify the taxonomic affiliation of the underlying taxa and to speed up their formal characterization and description ( 28 ). Owing to user requests, we also provide our data in, e.g. the JSON format. We are happy to consider requests for additional formats and data releases. UNITEterm·dom is a LinkOut provider for GenBank, which links their full-length fungal ITS sequences to the corresponding SH pages in UNITEterm·dom. Since 2018, UNITEterm·dom is also a data and link provider for the Global Biodiversity Information Facility ( https://www.gbif.org/ ). This allows sequence-based observations of fungi annotated against the UNITEterm·dom SH system to be indexed by and queried through GBIF. SHs became the first system to allow for incorporation of molecularly detected and molecularly identified biodiversity data into GBIF′s global data pool, currently dominated by morphological evidence from natural history collections and citizen science projects. In addition to scientific use, GBIF-mediated data are used for biodiversity assessments in global policy making and conservation efforts. Dataset exports by users The fact that UNITEterm·dom implements a range of scientific standards means that the user can tailor pretty much any imaginable query governed by those standards. For example, it is possible to download all sequences from the built environment or sequences collected above some specific altitude or in Swedish forests, owing to the MIxS-BE and other standards. Targeting sequences isolated from ferns, the genus Eucalyptus or aquatic environments is similarly straightforward, as is targeting pathogenic or human-associated fungi. Downloads can be made in a number of formats, including FASTA, comma-separated values, as well as user-specified exports. UNITEterm·dom WEBSITE The UNITEterm·dom website ( https://uniteterm·dom.ut.ee ) provides direct access to all SHs, all release files, and all metadata. The data are made available under the CC BY-SA 4.0 software license. No registration or login is needed to download data or do basic metadata and sequence searches. However, to access the more advanced features of UNITEterm·dom, registration is necessary. Registration is a tiered process, where basic registration opens up all data access and download features. Modifying or depositing data requires additional clearance, and a sophisticated system is in place to allow control of what specific users may and may not do. A review-type process operates to vet data and annotations provided by users. Registered users can apply to become curators of specific taxa (e.g. the family Cantharellaceae), which enables them to re-annotate sequences and provide new metadata for those taxa. Documented taxonomic expertise is needed to become a curator of specific groups. Species hypothesis system All SHs have a unique URL where the underlying multiple sequence alignments and pertinent metadata are displayed. The fact that each SH has a unique DOI makes them communicable across datasets and studies, even if an SH lacks a meaningful taxonomic annotation altogether (e.g. ‘Uncultured fungus’). UNITEterm·dom employs the DOI versioning system, such that it is possible to track SH sequence inclusiveness over time. It is, thus, always possible to establish exactly what sequences were part of some particular SH at some specific point in time. We encourage users to explore their fungi of interest in our system, which brings together and visualizes sequences and their metadata in a way that the INSDC cannot (Figure 1 ). Figure 1. A screenshot of a UNITEterm·dom SH Digital Object Identifier (DOI) page for Tomentella atroarenicolor ( https://plutof.ut.ee/#/datacite/10.15156%2FBIO%2FSH009889.07FU ). ( A ) The most accurate taxon name chosen automatically (or manually, if the default was overridden by an expert user) from the available sequence identifications. ( B ) Short ID of the DOI. ( C ) Data on reference sequence chosen to represent this SH. ( D ) Placement of the SH in the fungal classification and identification records for individual sequences. The number after the taxon name indicates how many sequences that carry that name. ( E ) Select statistics on the SH. The minimum distance 3.0% is the mandatory genetic difference between sister SHs. ( F ) Distribution map of the individual sequences. ( G ) Information on ecology (interacting taxa) if associated with the individual sequences. ( H ) DataCite-specific data on the DOI. ( I ) Images of the specimen or sample from which the DNA was extracted. Only a limited number of sequences have images attached to them. ( J ) Graphical overview of the SH with detailed information. ( K ) SH inclusiveness across sequence similarity threshold values. A threshold value ( = minimum distance) of 1.5% will split these sequences into two SHs, shown here in different colours. ( L ) A threshold value of 2.5% will lump all sequences into a single SH. Each such SH is hyperlinked to its own unique web page. ( M ) Scrollable multiple sequence alignment of the SH. ‘RefSeq’ indicates that the sequence was selected manually to be the representative sequence for the SHs. RefSeqs stem from type specimens or other authentic and particularly trustworthy material. This particular SH contains both INSDC sequences (brown) and sequences that are only found in UNITEterm·dom (yellow). Some 29 000 sequences are only found in UNITEterm·dom at this stage, but will be submitted to the INSDC upon publication of the underlying studies. These sequences are included in the various UNITEterm·dom sequence releases and download files. Identification services Although UNITEterm·dom is primarily a data provider rather than a metabarcoding or sequence analysis software pipeline, we do provide basic means for establishing the taxonomic affiliation of newly generated fungal ITS sequences. A multi-query BLAST service is provided, as is a function to assign sets of sequences to SHs. These searches enjoy the 23 000+ taxonomic re-annotations provided by the UNITEterm·dom community, such that queries in UNITEterm·dom offer information that is not present in the INSDC. All re-annotations are shown with original data, and although UNITEterm·dom shares re-annotations with other sequence databases including the INSDC, many of them operate under policies that do not permit changing names or other conceptual aspects of sequences before obtaining written consent by the original sequence authors. OUTLOOK The rapid development of single-molecule high-throughput sequencing technologies is enabling novel approaches to generating high-quality sequences spanning the full nuclear ribosomal operon, including the SSU, ITS and LSU markers in their entirety ( 29 ). We have begun collaborating and exchanging results with the SILVA database ( 30 ), which targets the prokaryotic and eukaryotic SSU and LSU genes but not the intercalary eukaryotic ITS region. The fairly conserved SSU and LSU genes offer the advantage of robust phylogenetic assignment of newly generated sequence data at the phylum, class, and order levels (and often further), however at the expense of resolution at the species and sometimes genus and family levels ( 31–32 ). Improved UNITE-SILVA collaboration would offer both robust phylogenetic placement and unambiguous communicability at the species level, a much sought-after combination ( 33 ). UNITEterm·dom will continue to dynamically provide versions of the SH taxonomies to the GBIF backbone taxonomy, and molecular occurrence data from specimens and metabarcoding samples will become discoverable through https://www.gbif.org as well. We hope and expect that extending the mapping of biodiversity into the molecular realm will lead to richer and unbiased biodiversity evidence to positively impact global modelling and decision-making. UNITEterm·dom seeks to provide resolved taxonomic information for fungal ITS sequences across the fungal tree of life, and employs several mechanisms to try to ensure that. However, the taxonomic placement infers only a part of the biology of an organism. Recently, we have begun to collaborate with the FUNGuild database ( 34 ) to provide information on the functional guild assignments of the fungal species and groups in UNITEterm·dom. We will shortly be able to show not only taxonomic names, but also the functional guilds of those fungi (e.g. mycorrhizal, animal parasitic, or saprotrophic). The user will thus obtain not only a taxonomic, but also a functional/ecological, fingerprint of the fungal community at hand. FUNGuild presently associates functional guilds at the family, genus, and species name levels, which presents a potential problem since these taxonomic ranks can include genera, species, or strains, respectively, with divergent ecological lifestyles. To address this issue, UNITEterm·dom will include the assigned level of confidence provided by FUNGuild for each assignment to assist user interpretation. We also anticipate being able to associate assignments with individual DNA sequences (fungal individuals), such that a closer UNITE-FUNGuild collaboration—where all data are fed in both directions—would be able to provide highly detailed information on functional aspects of fungal communities to users of UNITEterm·dom and FUNGuild alike. The UNITEterm·dom database is an open source, open access initiative driven by the mycological community. UNITEterm·dom has a history of adapting to the needs and wants of the mycological community, and we mean to keep it that way. Any feature request forwarded to the UNITEterm·dom staff will be considered for implementation, and all such implementations will be made freely available to the scientific community at large. FUNDING Alfred P. Sloan Foundation [G-2015-14062]; Swedish Research Council of Environment, Agricultural Sciences, and Spatial Planning [FORMAS, 215-2011-498]; European Regional Development Fund (Centre of Excellence EcolChange) [TK131]; Estonian Research Council [IUT20-30]. Funding for open access charge: Swedish Research Council of Environment, Agricultural Sciences and Spatial Planning. Conflict of interest statement . None declared.

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• Eponymous or retrospective terms (e.g. “Nash equilibrium”, “segregation”) do not appear in the original source and so are not highlighted — a deliberate choice (see Report 4).
• Some entries begin with a word in capitals. EVIDENCE CORRECTED means the finding still stands and it was our quotation that was wrong — it has been replaced. RETRACTED means the entry itself was wrong; it stays on the page, marked, with its reason, rather than being deleted. WITHDRAWN AND REPLACED means a corrected version of it appears in the entries below. Each mark carries its own reason, because the reasons differ from one entry to the next. An entry we have WITHDRAWN is removed from this page and kept in the record, with its reason. A line reading Audit and a date is a later re-reading of the entry against its whole sentence: DOUBTFUL means it was kept, and the reason says what is loose about it.
• Quotation marks inside the tagger's sentence. Where a tag is the tagger's own sentence, a phrase in quotation marks inside it is borrowed from the paper — the tagger's wording around it is not. The paper's own sentence is the evidence quote shown on the same row, so the borrowing can be checked against the thing borrowed from without leaving this page. Nothing inside quotation marks anywhere on this page is ours: if it is quoted, it is the paper's. Whose words a concept carries. A concept entry records a term the paper itself uses, so the term, the sense given for it, and its evidence are the paper's own words, quoted where the paper fixes them. This is the opposite of a sense entry in the tag table, which is the tagger's sentence about how the paper uses a term. Where a concept entry could not be grounded in the paper's words, the entry says so on its own row.
• Counts: 1 work · 1 date.
Meta-Tagging Project · record nilsson2018-the-unite-database-for-molecular-identification-of.
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