„Ursprünge der Viren“ – Versionsunterschied

aus Wikipedia, der freien Enzyklopädie
Zur Navigation springen Zur Suche springen
Versionsgeschichte interaktiv durchsuchen
[ungesichtete Version][gesichtete Version]
← Zum vorherigen VersionsunterschiedZum nächsten Versionsunterschied →
Inhalt gelöscht Inhalt hinzugefügt
VisuellWikitext
Added link
Übersetzung von en:Realm (virology)#Origins
Zeile 1: Zeile 1:
Im Gegensatz zu den drei [[Domäne (Biologie)|Domänen]] der [[zelluläre Organismen|zellulären Organismen]] - [[Archaea]], [[Bacteria]] und [[Eukarya]] (Archaeen, Bakterien und Eukaryoten – komplex-zellulären Organismen), die einen gemeinsamen Vorfahren ([[Urvorfahr]]en) haben, besteht zwischen den [[Viren|Virus]]-[[Realm (Virologie)|Realms]] im Allgemeinen keine genetische Beziehung, die auf gemeinsamer Abstammung beruht.
{{Short description|Taxonomic rank}}
Selbst innerhalb der einzelnen Realms stammen die Mitglieder nicht unbedingt von einem gemeinsamen Vorfahren ab.
In [[virology]], '''realm''' is the highest taxonomic rank established for [[virus]]es by the [[International Committee on Taxonomy of Viruses]] (ICTV), which oversees virus taxonomy. Six virus realms are recognized and united by specific [[Conserved sequence|highly conserved]] traits:
Die Realms sind so definiert (charakterisiert), dass sie Gruppen von Viren auf der Grundlage [[konservierung|hochkonservierter]] [[Merkmal#Biologie|Merkmale]] zusammenfassen, d. h. nicht auf der Grundlage einer gemeinsamen Abstammung, wie sie als Grundlage für die Taxonomie des zellulären Lebens dient.
Jeder Realm der Viren stellt daher mindestens eine Instanz der Entstehung von Viren dar.<ref name="ICTV_nScope"/>
Im einzelnen:


== ''Adnaviria'' ==
* ''[[Adnaviria]]'', which contains archaeal filamentous viruses with A-form double-stranded (ds) DNA genomes encoding a unique alpha-helical major capsid protein;
Der Ursprung der [[Archaeen]] parasitierenden ''[[Adnaviria]]'' ist unbekannt (Stand 2020). Es wird aber vermutet, dass Vertreter der ''Adnaviria'' schon seit langer Zeit existieren, und dass sie bereits den letzten gemeinsamen Vorfahren der (heutigen) Archaeen ({{enS|last archaeal common ancestor}}, [[Urvorfahr#LACA|LACA]]) infiziert haben könnten.<ref name="Krupovic2020" />
* ''[[Duplodnaviria]]'', which contains all dsDNA viruses that encode the HK97-fold major capsid protein;
* ''[[Monodnaviria]]'', which contains all single-stranded DNA (ssDNA) viruses that encode a [[HUH-tag|HUH superfamily endonuclease]] and their descendants;
* ''[[Riboviria]]'', which contains all RNA viruses that encode [[RNA-dependent RNA polymerase]] and all viruses that encode [[reverse transcriptase]];
* ''[[Ribozyviria]]'', which contains hepatitis delta-like viruses with circular, negative-sense ssRNA genomes;
* and ''[[Varidnaviria]]'', which contains all dsDNA viruses that encode a vertical [[Jelly roll fold|jelly roll]] major capsid protein.


== ''Duplodnaviria'' ==
The rank of realm corresponds to the rank of [[Domain (biology)|domain]] used for cellular life, but differs in that viruses in a realm do not necessarily share a common ancestor based on [[common descent]] nor do the realms share a common [[YNW Melly|ancestor]]. Instead, realms group viruses together based on specific traits that are highly conserved over time, which may have been obtained on a single occasion or multiple occasions. As such, each realm represents at least one instance of viruses coming into existence. While historically it was difficult to determine deep evolutionary relations between viruses, in the 21st century methods such as [[metagenomics]] and [[cryogenic electron microscopy]] have enabled such research to occur, which led to the establishment of ''Riboviria'' in 2018, three realms in 2019, and two in 2020.
Der Realm ''[[Duplodnaviria]]'' ist entweder [[monophyletisch]] oder [[polyphyletisch]]. Er geht möglicherweise sogar dem letzten „universellen“ gemeinsamen Ahn der heutigen [[zelluläre Organismen|zellulären Organismen]] ({{enS|last universal common ancestor}}, [[Urvorfahr|LUCA]], auch {{lang|en|''most recent common ancestor''}}, [[Most recent common ancestor|MRCA]]) voraus.
Der genaue Ursprung des Realms ist nicht bekannt. Von allen Mitgliedern wird ein Haupt[[kapsidprotein]] (MCP) mit einer [[Proteinfaltung|Faltung]] wie bei [[Escherichia-Virus HK97]] ([[Nomenklatur|wissenschaftlich]] ''Byrnievirus HK97'') [[Genetischer Code|kodiert]] und daher als HK97-MCP bezeichnet. Diese Proteinfaltung kommt außerhalb des Realms nur bei der [[Proteinfamilie]] der [[Encapsulin]]e bei [[Bakterien]] und [[Archaeen]] vor, wie es [[Encapsulin-Nanokompartiment|Nanokompartimente]] ausbildet, die [[Ferritin]]-artige Proteine und [[Peroxidasen]] einkapseln, die vor [[Oxidativer Stress|oxidativem Stress]] schützen.<ref name="McHugh2014"/><ref>[https://www.ebi.ac.uk/interpro/entry/pfam/PF04454/ Pfam PF04454] Encapsulating protein for peroxidase: Linocin_M18.</ref>
Die Beziehung zwischen den ''Duplodnaviria '' und diesen Nanokompartimenten ist noch nicht vollständig verstanden (Stand 2020).<ref name="ICTV_Duplodnaviria" /><ref name="Krupovic2017" /><ref name="Krupovic2020" />


== ''Monodnaviria'' ==
==Naming==
Der Realm ''[[Monodnaviria]]'' ist [[polyphyletisch]], er scheint sich mehrfach aus zirkulären [[Plasmid]]en von [[Bakterien]] und [[Archaeen]] entwickelt zu haben. Das sind DNA-[[Molekül]]e außerhalb des Archaeen- bzw. [[Bakterienchromosom]]s, die sich im Innern dieser Archaeen bzw. Bakterien selbst [[Replikation|replizieren]].<ref name="ICTV_Monodnaviria" /><ref name="Kazlauskas2019"/>
The names of realms consist of a descriptive first part and the suffix -''viria'', which is the suffix used for virus realms.<ref name=ictvcode >{{cite web|title=ICTV Code The International Code of Virus Classification and Nomenclature|url=https://ictv.global/about/code|website=International Committee on Taxonomy of Viruses (ICTV)|access-date=18 March 2020|language=en|date=October 2018}}</ref> The first part of ''Duplodnaviria'' means "double DNA", referring to dsDNA viruses,<ref name=duplo >{{cite web|vauthors=Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH|title=Create a megataxonomic framework, filling all principal/primary taxonomic ranks, for dsDNA viruses encoding HK97-type major capsid proteins|url=https://ictv.global/ictv/proposals/2019.004G.zip|website=International Committee on Taxonomy of Viruses|access-date=13 August 2020|language=en|format=docx|date=18 October 2019}}</ref> the first part of ''Monodnaviria'' means "single DNA", referring to ssDNA viruses,<ref name=mono >{{cite web|vauthors=Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH|title=Create a megataxonomic framework, filling all principal taxonomic ranks, for ssDNA viruses|url=https://ictv.global/ictv/proposals/2019.005G.zip|website=International Committee on Taxonomy of Viruses|access-date=13 August 2020|language=en|format=docx|date=18 October 2019}}</ref> the first part of ''Riboviria'' is taken from '''ribo'''nucleic acid (RNA),<ref name=ribo >{{cite web|vauthors=Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH|title=Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria|url=https://ictv.global/ictv/proposals/2019.006G.zip|website=International Committee on Taxonomy of Viruses (ICTV)|access-date=13 August 2020|language=en|format=docx|date=18 October 2019}}</ref> and the first part of ''Varidnaviria'' means "various DNA".<ref name=vari >{{cite web|vauthors=Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH|title=Create a megataxonomic framework, filling all principal taxonomic ranks, for DNA viruses encoding vertical jelly roll-type major capsid proteins|url=https://ictv.global/ictv/proposals/2019.003G.zip|website=International Committee on Taxonomy of Viruses|access-date=13 August 2020|language=en|format=docx|date=18 October 2019}}</ref> For [[viroid]]s, the suffix is designated as -''viroidia'', and for [[Satellite (biology)|satellites]], the suffix is -''satellitia'',<ref name=ictvcode /> but as of 2019 neither viroid nor satellite realms have been designated.<ref name=ictv >{{cite web|url=https://ictv.global/taxonomy|title=Virus Taxonomy: 2019 Release|website=International Committee on Taxonomy of Viruses|publisher=International Committee on Taxonomy of Viruses|access-date=25 April 2020}}</ref>


==Realms==
== ''Riboviria'' ==
Der Realm ''[[Riboviria]]'' ist entweder [[monophyletisch]] oder [[polyphyletisch]].
===''Duplodnaviria''===
[[File:Duplodnaviria_virion_morphology.jpg|thumb|Illustrated sample of ''Duplodnaviria'' virions]]
''[[Duplodnaviria]]'' contains double-stranded DNA (dsDNA) viruses that encode a major capsid protein (MCP) that has the HK97 fold. Viruses in the realm also share a number of other characteristics involving the capsid and capsid assembly, including an icosahedral capsid shape and a terminase enzyme that packages viral DNA into the capsid during assembly. Two groups of viruses are included in the realm: tailed bacteriophages, which infect prokaryotes and are assigned to the order ''[[Caudovirales]]'', and herpesviruses, which infect animals and are assigned to the order ''[[Herpesvirales]]''.<ref name=duplo />


Die [[Reverse Transkriptase]] (RT) im [[Reich (Biologie)|Virusreich]] ''[[Pararnavirae]]'' hat sich wahrscheinlich bei einer einzigen Gelegenheit aus einem [[Retrotransposon]] entwickelt (einer Art von selbstreplizierendem DNA-[[Molekül]], das sich durch [[reverse Transkription]] [[Replikation|repliziert]].
The relation between caudoviruses and herpesviruses is not certain, as they may either share a common ancestor or herpesviruses may be a divergent clade from within ''Caudovirales''. A common trait among duplodnaviruses is that they cause latent infections without replication while still being able to replicate in the future.<ref>{{cite journal|vauthors=Weidner-Glunde M, Kruminis-Kaszkiel E, Savanagoudar M|date=February 2020|title=Herpesviral Latency—Common Themes|journal=Pathogens|volume=9|issue=2|pages=125|doi=10.3390/pathogens9020125|pmc=7167855|pmid=32075270|doi-access=free}}</ref><ref>{{cite web|title=Virus latency|url=https://viralzone.expasy.org/3970|website=ViralZone|publisher=Swiss Institute of Bioinformatics|access-date=27 August 2020}}</ref> Tailed bacteriophages are ubiquitous worldwide,<ref>{{cite journal|vauthors=Andrade-Martínez JS, Moreno-Gallego JL, Reyes A|date=August 2019|title=Defining a Core Genome for the Herpesvirales and Exploring their Evolutionary Relationship with the Caudovirales|journal=Sci Rep|volume=9|issue=1|pages=11342 |doi=10.1038/s41598-019-47742-z|pmc=6683198|pmid=31383901|bibcode=2019NatSR...911342A}}</ref> important in marine ecology,<ref>{{cite journal|vauthors=Wilhelm SW, Suttle CA|date=October 1999|title=Viruses and Nutrient Cycles in the Sea: Viruses play critical roles in the structure and function of aquatic food webs|journal=BioScience|volume=49|issue=10|pages=781–788|doi=10.2307/1313569|jstor=1313569|doi-access=free}}</ref> and the subject of much research.<ref>{{cite journal|vauthors=Keen EC|date=January 2015|title=A century of phage research: Bacteriophages and the shaping of modern biology|journal=BioEssays|volume=37|issue=1|pages=6–9|doi=10.1002/bies.201400152|pmc=4418462|pmid=25521633}}</ref> Herpesviruses are known to cause a variety of epithelial diseases, including [[herpes simplex]], [[chickenpox]] and [[shingles]], and [[Kaposi's sarcoma]].<ref>{{cite journal|vauthors=Kukhanova MK, Korovina AN, Kochetkov SN|date=December 2014|title=Human herpes simplex virus: life cycle and development of inhibitors|journal=Biochemistry (Mosc)|volume=79|issue=13|pages=1635–1652|doi=10.1134/S0006297914130124|pmid=25749169|s2cid=7414402}}</ref><ref>{{cite journal|vauthors=Gershon AA, Breuer J, Cohen JI, Cohrs RJ, Gershon MD, Gilden D, Grose C, Hambleton S, Kennedy PG, Oxman MN, Seward JF, Yamanishi K|date=2 July 2015|title=Varicella zoster virus infection|journal=Nat Rev Dis Primers|volume=1|pages=15016|doi=10.1038/nrdp.2015.16|pmc=5381807|pmid=27188665}}</ref><ref>{{cite journal|vauthors=O'Leary JJ, Kennedy MM, McGee JO|date=February 1997|title=Kaposi's sarcoma associated herpes virus (KSHV/HHV 8): epidemiology, molecular biology and tissue distribution|journal=Mol Pathol|volume=50|issue=1|pages=4–8|doi=10.1136/mp.50.1.4|pmc=379571|pmid=9208806}}</ref>


Der Ursprung der [[RNA-abhängige RNA-Polymerase|RNA-abhängigen RNA-Polymerase]] (RdRp) im Virusreich ''[[Orthornavirae]]'' ist weniger sicher.
===''Monodnaviria''===
Es es wurde einerseits vermutet, dass die RdRP entweder von einem bakteriellen [[Intron#Selbstspleißende Introns|Intron der Gruppe II]] abstammen, das für Reverse Transkriptase (RT) [[Genetischer Code|kodiert]].
''[[Monodnaviria]]'' contains single-stranded DNA (ssDNA) viruses that encode an [[endonuclease]] of the HUH superfamily that initiates [[rolling circle replication]] and all other viruses descended from such viruses. The prototypical members of the realm are called CRESS-DNA viruses and have circular ssDNA genomes. ssDNA viruses with linear genomes are descended from them, and in turn some dsDNA viruses with circular genomes are descended from linear ssDNA viruses.<ref name=mono />
Sie könnte aber auch bereits vor dem letzten „universellen“ gemeinsamen Ahn der heutigen [[zelluläre Organismen|zellulären Organismen]] ([[Urvorfahr|LUCA]]) entstanden sein, wenn dieser Nachkomme von [[Ribozyt]]en einer urzeitlichen [[RNA-Welt]] war. Die ''Orthornavirae'' könnten dann den RT des heutigen zellulären Lebens mit DNA-[[Genom]] vorausgehen.<ref name="ICTV_Riboviria"/><ref name="Wolf2018"/><ref name="Krupovic2020"/>
Eine größere Studie aus dem Jahr 2022, in der neue Viren-[[Phylum|Phyla]] beschrieben wurden, legt die Annahme nahe, dass RNA-Viren von der RNA-Welt abstammen. Die [[Retroelement]]e der heutigen zellulären Organismen könnten dann von einem Vorfahren abstammen, der mit dem Phylum ''[[Lenarviricota]]'' verwandt ist; Mitglieder eines neu entdeckten ''Orthornavirae''-Phylums (vorgeschlagene Bezeichnung „''[[Orthornavirae#Systematik|Taraviricota]]''“) sollten danach die Vorfahren aller RNA-Viren sein.<ref name="Zayed2022"/>


== ''Ribozyviria'' ==
CRESS-DNA viruses include three kingdoms that infect prokaryotes: ''[[Loebvirae]]'', ''[[Sangervirae]]'', and ''[[Trapavirae]]''. The kingdom ''[[Shotokuvirae]]'' contains eukaryotic CRESS-DNA viruses and the atypical members of ''Monodnaviria''.<ref name=mono /> Eukaryotic monodnaviruses are associated with many diseases, and they include [[papillomavirus]]es and [[polyomavirus]]es, which cause many cancers,<ref>{{cite web|title=Papillomaviridae|url=https://viralzone.expasy.org/5|website=ViralZone|publisher=Swiss Institute of Bioinformatics|access-date=27 August 2020}}</ref><ref>{{cite web|title=Polyomaviridae|url=https://viralzone.expasy.org/148|website=ViralZone|publisher=Swiss Institute of Bioinformatics|access-date=27 August 2020}}</ref> and [[geminivirus]]es, which infect many economically important crops.<ref>{{cite journal|vauthors=Malathi VG, Renuka Devi P|date=March 2019|title=ssDNA Viruses: Key Players in Global Virome|journal=Virusdisease|volume=30|issue=1|pages=3–12|doi=10.1007/s13337-019-00519-4|pmc=6517461|pmid=31143827}}</ref>
Der Ursprung des realms ''[[Ribozyviria]]'' ist unbekannt. Es wurde vorgeschlagen, dass sie sich von [[Retrozyme]]n (einer Familie von [[Retrotransposon]]s<ref name="Cervera2016"/>) oder einem viroidähnlichen Element (d.&nbsp;h. einem [[Viroid]] oder [[Satellit (Biologie)|Satellit]]) durch Einfanhg eines [[Kapsidprotein]] ableiten könnten.<ref name="Lee2022"/>


===''Riboviria''===
== ''Varidnaviria'' ==
Der Realm ''[[Varidnaviria]]'' ist entweder [[monophyletisch]] oder [[polyphyletisch]] und geht möglicherweise (ebenfalls) dem [[Urvorfahr|letzten universellen gemeinsamen Ahn]] (LUCA) der heutigen zellulären Organismen voraus.
''[[Riboviria]]'' contains all RNA viruses that encode an [[RNA-dependent RNA polymerase]] (RdRp), assigned to the kingdom ''[[Orthornavirae]]'', and all reverse transcribing viruses, i.e. all viruses that encode a [[reverse transcriptase]] (RT), assigned to the kingdom ''[[Pararnavirae]]''. These enzymes are vital in the viral life cycle, as RdRp transcribes viral mRNA and replicates the genome, and RT likewise replicates the genome.<ref name=ribo /> ''Riboviria'' mostly contains eukaryotic viruses, and most eukaryotic viruses, including most human, animal, and plant viruses, belong to the realm.<ref name=wolf >{{cite journal|vauthors=Wolf YI, Kazlauskas D, Iranzo J, Lucia-Sanz A, Kuhn JH, Krupovic M, Dolja VV, Kooning EV|date=27 November 2018|title=Origins and Evolution of the Global RNA Virome|journal=mBio|volume=9|issue=6|pages=e02329-18|doi=10.1128/mBio.02329-18|pmc=6282212|pmid=30482837}}</ref>
Das Viren[[Reich (Biologie)|reich]] ''[[Bamfordvirae]]'' ist wahrscheinlich aus dem anderen Reich ''[[Helvetiavirae]]'' durch Verschmelzung zweier Haupt[[kapsidprotein]]e (MCPs) entstanden, so dass es als Ergebnis nun ein einziges MCP mit zwei [[Jelly-Roll-Faltung]]en ({{lang|en|double jelly roll}}, DJR) anstelle von einer gibt.
Die (vermutlich ursprünglichen) MCPs der ''Helvetiavirae'' mit einer einzigen Jelly-Roll-Faltung ({{lang|en|single jelly roll}}, SJR) stehen in Beziehung zu einer Gruppe von Proteinen, die die ebenfalls SJR-Faltungen enthalten, darunter die [[Cupin-Superfamilie]]<ref>[https://www.ebi.ac.uk/interpro/entry/pfam/PF00190/ Pfam PF00190] Cupin.</ref> und die [[Nukleoplasmin]]e.<ref>InterPro: [https://www.ebi.ac.uk/interpro/entry/InterPro/IPR004301/ F IPR004301] Nucleoplasmin family.</ref>


Die [[Archaeen]] parasitierenden [[dsDNA]]-Viren der Familie ''[[Portogloboviridae]]'' (bisher keinem Realm sicher zugeodnet) enthalten nur ein vertikales SJR-MCP, das bei den ''[[Halopanivirales]]'' (''Helvetiavirae'') anscheinend verdoppelt wurde, so dass das MCP der ''Portogloboviridae'' wahrscheinlich eine frühere Stufe in der Evolutionsgeschichte der ''Varidnaviria''-MCPs darstellt.<ref name="ICTV_Varidnaviria"/><ref name="Krupovic2017"/><ref name="Krupovic2020"/>
Most widely known viral diseases are caused by viruses in ''Riboviria'', which includes [[influenza virus]]es, [[HIV]], [[coronavirus]]es, [[ebolavirus]]es, and the [[rabies virus]],<ref name=ictv /> as well as the first virus to be discovered, ''[[Tobacco mosaic virus]]''.<ref>{{cite journal|vauthors=Harrison BD, Wilson TM|date=29 March 1999|title=Milestones in the Research on Tobacco Mosaic Virus|journal=Philos Trans R Soc Lond B Biol Sci|volume=354|issue=1383|pages=521–529|doi=10.1098/rstb.1999.0403|pmc=1692547|pmid=10212931}}</ref> Reverse transcribing viruses are a major source of horizontal gene transfer by means of becoming endogenized in their host's genome, and a significant portion of the human genome consists of this viral DNA.<ref>{{cite journal|vauthors=Aiewsakun P, Katzourakis A|date=May 2015|title=Endogenous Viruses: Connecting Recent and Ancient Viral Evolution|journal=Virology|volume=479-480|pages=26–37|doi=10.1016/j.virol.2015.02.011|pmid=25771486|doi-access=free}}</ref>


Später (2021/2022) wurde jedoch ein anderes Szenario vorgeschlagen, bei dem die beiden Reiche ''Bamfordvirae'' und ''Helvetiavirae'' unabhängig voneinander entstanden sind. Dies wierd unterstützt durch die Beobachtung, dass das DJR-MCP-Protein der ''Bamfordvirae'' mit dem bakteriellen Protein [[DUF 2961]].<ref>[https://unilectin.unige.ch/propeller/display?protein_id=7678&name=DUF2961%20domain-containing%20protein DUF2961 domain-containing protein]. Auf: PropLec.</ref><ref>[[National Center for Biotechnology Information|NCBI]] Protein: [https://www.ncbi.nlm.nih.gov/protein/WP_144127294 DUF2961 domain-containing protein <nowiki>[Catellatospora sichuanensis]</nowiki>] NCBI Reference Sequence: WP_144127294.1.</ref> verwandt ist, was zu einer Reorganisation des Reiches ''Varidnaviria'' führen könnte.
===''Varidnaviria''===
Eine molekularphylogenetische Analyse legt nahe, dass die ''Helvetiavirae'' nicht an der Entstehung des DJR-MCP der ''Bamfordvirae'' beteiligt waren und dass sie wahrscheinlich aus der Klasse ''[[Tectiliviricetes]]'' (Phylum ''[[Preplasmiviricota]]'' der ''Bamfordvirae'') stammen.<ref name="Woo2021"/>
[[File:2w0c_monomer.png|thumb|A [[ribbon diagram]] of the MCP of ''[[Pseudoalteromonas virus PM2]]'', with the two jelly roll folds colored in red and blue]]
''[[Varidnaviria]]'' contains DNA viruses that encode MCPs that have a [[jelly roll fold]] folded structure in which the jelly roll (JR) fold is perpendicular to the surface of the viral capsid. Many members also share a variety of other characteristics, including a minor capsid protein that has a single JR fold, an ATPase that packages the genome during capsid assembly, and a common [[DNA polymerase]]. Two kingdoms are recognized: ''[[Helvetiavirae]]'', whose members have MCPs with a single vertical JR fold, and ''[[Bamfordvirae]]'', whose members have MCPs with two vertical JR folds.<ref name=vari />


Es ist also möglich, dass sich das DJR-MCP der ''Bamfordvirae'' unabhängig von diesem Protein entwickelt hat, aber die Entstehung des DJR-MCP durch Duplikation des SJR-MCP der ''Helvetiavirae'' kann derzeit (2022) noch nicht ausgeschlossen werden.<ref name="Krupovic2022"/>
Marine viruses in ''Varidnaviria'' are ubiquitous worldwide and, like tailed bacteriophages, play an important role in marine ecology.<ref>{{cite journal|vauthors=Kauffman KM, Hussain FA, Yang J, Arevalo P, Brown JM, Chang WK, VanInsberghe D, Elsherbini J, Sharma RS, Cutler MB, Kelly L, Polz MF|date=1 February 2018|title=A Major Lineage of Non-Tailed dsDNA Viruses as Unrecognized Killers of Marine Bacteria|journal=Nature|volume=554|issue=7690|pages=118–122|doi=10.1038/nature25474|pmid=29364876|bibcode=2018Natur.554..118K|s2cid=4462007}}</ref> Most identified eukaryotic DNA viruses belong to the realm.<ref name=krupovic2015 >{{cite journal|vauthors=Krupovic M, Koonin EV|date=February 2015|title=Polintons: a hotbed of eukaryotic virus, transposon and plasmid evolution|journal=Nat Rev Microbiol|volume=13|issue=2|pages=105–115|doi=10.1038/nrmicro3389|pmc=5898198|pmid=25534808}}</ref> Notable disease-causing viruses in ''Varidnaviria'' include [[adenovirus]]es, [[poxvirus]]es, and the [[African swine fever virus]].<ref name=ictv /> Poxviruses have been highly prominent in the history of modern medicine, especially ''Variola virus'', which caused [[smallpox]].<ref>{{cite journal|vauthors=Meyer H, Ehmann R, Smith GL|date=February 2020|title=Smallpox in the Post-Eradication Era|journal=Viruses|volume=12|issue=2|pages=138|doi=10.3390/v12020138|pmc=7077202|pmid=31991671|doi-access=free}}</ref> Many varidnaviruses are able to become endogenized, and a peculiar example of this are [[virophage]]s, which confer protection for their hosts against [[giant virus]]es during infection.<ref name=krupovic2015 />


== Genetische Beziehungen zwischen den Virus-Realms ==
===''Adnaviria''===
Obwohl die Realms im Allgemeinen keine genetische Beziehung zueinander haben, gibt es einige Ausnahmen:
Realm ''Adnaviria'' unifies archaeal filamentous viruses with linear A-form double-stranded DNA genomes and characteristic major capsid proteins unrelated to those encoded by other known viruses.<ref name=Adnaviria>{{cite journal |last1=Krupovic |first1=M |last2=Kuhn |first2=JH |last3=Wang |first3=F |last4=Baquero |first4=DP |last5=Dolja |first5=VV |last6=Egelman |first6=EH |last7=Prangishvili |first7=D |last8=Koonin |first8=EV |title=''Adnaviria'': a new realm for archaeal filamentous viruses with linear A-form double-stranded DNA genomes. |journal=Journal of Virology |date=12 July 2021 |volume=95 |issue=15 |pages=e0067321 |doi=10.1128/JVI.00673-21 |pmid=34011550 |pmc=8274609 }}</ref> The realm currently includes viruses from three families, ''[[Lipothrixviridae]]'', ''[[Rudiviridae]]'', and ''[[Tristromaviridae]]'', all infecting hyperthermophilic archaea. The nucleoprotein helix of adnaviruses is composed of asymmetric units containing two MCP molecules, a homodimer in the case of rudivirids and a heterodimer of paralogous MCPs in the case of lipothrixvirids and tristromavirids.<ref>{{cite journal |last1=Wang |first1=F |last2=Baquero |first2=DP |last3=Beltran |first3=LC |last4=Su |first4=Z |last5=Osinski |first5=T |last6=Zheng |first6=W |last7=Prangishvili |first7=D |last8=Krupovic |first8=M |last9=Egelman |first9=EH |title=Structures of filamentous viruses infecting hyperthermophilic archaea explain DNA stabilization in extreme environments. |journal=Proceedings of the National Academy of Sciences of the United States of America |date=2020 |volume=117 |issue=33 |pages=19643–19652 |doi=10.1073/pnas.2011125117 |pmid=32759221 |pmc=7443925 |doi-access=free }}</ref><ref>{{cite journal |last1=Wang |first1=F |last2=Baquero |first2=DP |last3=Su |first3=Z |last4=Osinski |first4=T |last5=Prangishvili |first5=D |last6=Egelman |first6=EH |last7=Krupovic |first7=M |title=Structure of a filamentous virus uncovers familial ties within the archaeal virosphere. |journal=Virus Evolution |date=2020 |volume=6 |issue=1 |pages=veaa023 |doi=10.1093/ve/veaa023 |pmid=32368353 |url=https://academic.oup.com/ve/article/6/1/veaa023/5826649|pmc=7189273 }}</ref> The MCPs of ligamenviral particles have a unique α-helical fold first found in the MCP of rudivirid Sulfolobus islandicus rod-shaped virus 2 (SIRV2).<ref>{{cite journal |last1=DiMaio |first1=F |last2=Yu |first2=X |last3=Rensen |first3=E |last4=Krupovic |first4=M |last5=Prangishvili |first5=D |last6=Egelman |first6=EH |title=Virology. A virus that infects a hyperthermophile encapsidates A-form DNA. |journal=Science |date=2015 |volume=348 |issue=6237 |pages=914–7 |doi=10.1126/science.aaa4181 |pmid=25999507|pmc=5512286 }}</ref> All members of the ''Adnaviria'' share a characteristic feature in that the interaction between the MCP dimer and the linear dsDNA genome maintains the DNA in the A form. Consequently, the entire genome adopts the A form in virions. Like many structurally related viruses in the two other realms of dsDNA viruses (''Duplodnaviria'' and ''Varidnaviria''), there is no detectable sequence similarity among the capsid proteins of viruses from different tokiviricete families, suggesting a vast undescribed diversity of viruses in this part of the virosphere.


* Viren des [[Morphotyp]]s der [[Podoviridae]] (Klasse ''[[Caudoviricetes]]'' im Realm ''[[Duplodnaviria]]'') [[Genetischer Code|kodieren]] für eine [[DNA-Polymerase]], die mit den DNA-Polymerasen von vielen Mitgliedern im Realm ''[[Varidnaviria]]'' verwandt ist, die kodiert werden.<ref name="Krupovic2015" />
===''Ribozyviria''===
''Ribozyviria'' is characterised by the presence of genomic and antigenomic ribozymes of the ''[[Deltavirus]]'' type. Additional common features include a rod-like structure and a RNA-binding "delta antigen" encoded in the genome.<ref name=prop >{{cite web |vauthors=Hepojoki J, Hetzel U, Paraskevopoulou S, Drosten C, Harrach B, Zerbini M, Koonin EV, Krupovic M, Dolja V, Kuhn JH |title=Create one new realm (''Ribozyviria'') including one new family (''Kolmioviridae'') including genus ''Deltavirus'' and seven new genera for a total of 15 species |url=https://ictv.global/ictv/proposals/2020.012D.R.Ribozyviria.zip |format=docx |publisher=International Committee on Taxonomy of Viruses (ICTV) |date=6 December 2020 |access-date=27 May 2021 |language=en}}</ref>


* [[Eukaryoten]] parasitierende Viren im Reich ''[[Shotokuvirae]]'' (Realm ''[[Monodnaviria]]'') entstanden mehrfach durch [[Rekombination (Genetik)|Rekombinationsereignisse]], bei denen die DNA von Vorläufer[[plasmid]]en mit [[Komplementärstrang|komplementärer]] DNA (cDNA) von [[Virusklassifikation#Baltimore-Gruppe IV|RNA-Einzelstrang-Viren mit positiver Polarität]] aus dem Realm ''[[Riboviria]]'' kombiniert wurde, wodurch ssDNA-Viren der ''Shotokuvirae'' Kapsidproteine von RNA-Viren erhielten ([[Cruciviren]] oder RNA-DNA-[[Hybridvirus|Hybridviren]], RDHVs).<ref name="ICTV_Monodnaviria" /><ref name="Krupovic2017" />
==Origins==
In general, virus realms have no genetic relation to each other based on common descent, in contrast to the three domains of cellular life—[[Archaea]], [[Bacteria]], and [[Eukarya]]—which share a common ancestor. Likewise, viruses within each realm are not necessarily descended from a common ancestor since realms group viruses together based on highly conserved traits, not common ancestry, which is used as the basis for the taxonomy of cellular life. As such, each virus realm is considered to represent at least one instance of viruses coming into existence.<ref name=exec >{{cite journal|author=International Committee on Taxonomy of Viruses Executive Committee|date=May 2020|title=The New Scope of Virus Taxonomy: Partitioning the Virosphere Into 15 Hierarchical Ranks|journal=Nat Microbiol|volume=5|issue=5|pages=668–674|doi=10.1038/s41564-020-0709-x|pmc=7186216|pmid=32341570}}</ref> By realm:


* Die Familie ''[[Bidnaviridae]]'' im Realm ''[[Monodnaviria]]'' entstand durch die Integration eines Mitglieds der ''[[Parvoviridae]]'' (Realm ''[[Monodnaviria]]'') in ein [[Polinton]] (ein virusähnliches, [[DNA-Transposon|selbstreplizierendes DNA-Molekül]], das mit Viren im Realm ''[[Varidnaviria]]'' verwandt ist).
* ''Adnaviria'' is of unknown origin, but it has been suggested that viruses of ''Adnaviria'' have potentially existed for a long time, as it is thought that they may have infected the last archaeal common ancestor.<ref name=luca />
* ''Duplodnaviria'' is either monophyletic or polyphyletic and may predate the [[last universal common ancestor]] (LUCA) of cellular life. The exact origin of the realm is not known, but the HK97-fold MCP encoded by all members is, outside the realm, only found in [[encapsulin]]s, a type of nanocompartment found in bacteria, although the relation between ''Duplodnaviria'', and encapsulins is not fully understood.<ref name=duplo /><ref name=krupovic >{{cite journal|vauthors=Krupovic M, Koonin EV|date=21 March 2017|title=Multiple origins of viral capsid proteins from cellular ancestors|journal=Proc Natl Acad Sci U S A|volume=114|issue=12|pages=E2401–E2410|doi=10.1073/pnas.1621061114|pmc=5373398|pmid=28265094|doi-access=free}}</ref><ref name=luca >{{cite journal|last1=Krupovic|first1=M|last2=Dolja|first2=VV|last3=Koonin|first3=EV|title=The LUCA and its complex virome.|journal=Nat Rev Microbiol|date=14 July 2020|volume=18|issue=11|pages=661–670|doi=10.1038/s41579-020-0408-x|pmid=32665595|s2cid=220516514|url=https://bpp.oregonstate.edu/sites/agscid7/files/bpp/attachments/lucavirome2020.pdf|access-date=16 August 2020}}</ref>
* ''Monodnaviria'' is polyphyletic and appears to have emerged multiple times from bacterial and archaeal circular plasmids, which are extra-chromosomal DNA molecules that live inside of bacteria and archaea and which self-replicate.<ref name=mono /><ref>{{cite journal|vauthors=Kazlauskas D, Varsani A, Koonin EV, Krupovic M|date=31 July 2019|title=Multiple Origins of Prokaryotic and Eukaryotic Single-Stranded DNA Viruses From Bacterial and Archaeal Plasmids|journal=Nat Commun|volume=10|issue=1|pages=3425|doi=10.1038/s41467-019-11433-0|pmc=6668415|pmid=31366885|bibcode=2019NatCo..10.3425K}}</ref>
* ''Riboviria'' is monophyletic or polyphyletic. The reverse transcriptase of kingdom ''Pararnavirae'' likely evolved on a single occasion from a [[retrotransposon]], a type of self-replicating DNA molecule that replicates via [[reverse transcription]]. The origin of the RdRp of ''Orthornavirae'' is less certain, but they are believed to originate from a bacterial [[group II intron]] that encodes reverse transcriptase or to predate the LUCA being descendants of the ancient [[RNA world]] and precede reverse transcriptases of cellular life.<ref name=ribo /><ref name=wolf /><ref name=luca /> A larger study (2022) where new lieneages (phyla) were described, was in favor of the hypothesis that RNA viruses descend from the RNA world, suggesting that retroelements of cellular life originated from an ancestor related to the phylum ''[[Lenarviricota]]'' and that members of a newly discovered ''[[Taraviricota]]'' lineage (phylum) would be the ancestors of all RNA viruses.<ref>{{Cite journal|url=https://www.science.org/stoken/author-tokens/ST-419/full|title=Cryptic and abundant marine viruses at the evolutionary origins of Earth's RNA virome|date=April 8, 2022|journal=Science|volume=376|issue=6589|pages=156–162|doi=10.1126/science.abm5847|last1=Zayed|first1=Ahmed A.|last2=Wainaina|first2=James M.|last3=Dominguez-Huerta|first3=Guillermo|last4=Pelletier|first4=Eric|last5=Guo|first5=Jiarong|last6=Mohssen|first6=Mohamed|last7=Tian|first7=Funing|last8=Pratama|first8=Akbar Adjie|last9=Bolduc|first9=Benjamin|last10=Zablocki|first10=Olivier|last11=Cronin|first11=Dylan|last12=Solden|first12=Lindsey|last13=Delage|first13=Erwan|last14=Alberti|first14=Adriana|last15=Aury|first15=Jean-Marc|last16=Carradec|first16=Quentin|last17=Da Silva|first17=Corinne|last18=Labadie|first18=Karine|last19=Poulain|first19=Julie|last20=Ruscheweyh|first20=Hans-Joachim|last21=Salazar|first21=Guillem|last22=Shatoff|first22=Elan|last23=Bundschuh|first23=Ralf|last24=Fredrick|first24=Kurt|last25=Kubatko|first25=Laura S.|last26=Chaffron|first26=Samuel|last27=Culley|first27=Alexander I.|last28=Sunagawa|first28=Shinichi|last29=Kuhn|first29=Jens H.|last30=Wincker|first30=Patrick|pmid=35389782|bibcode=2022Sci...376..156Z |s2cid=248025736|display-authors=1}}</ref>
* ''Ribozyviria'' is of unknown origin. It has been proposed that they may have derived from [[Retrozyme|retrozymes]] (a family of [[retrotransposon|retrotransposons]]) or a viroid-like element (i.e. [[Viroid|viroids]] and [[Satellite (biology)|satellites]]) with capsid protein capture.<ref>{{Cite journal|last1=Lee|first1=Benjamin D.|last2=Koonin|first2=Eugene V.|date=2022-01-12|title=Viroids and Viroid-like Circular RNAs: Do They Descend from Primordial Replicators?|journal=Life|volume=12|issue=1|pages=103|doi=10.3390/life12010103|pmid=35054497 |pmc=8781251 |issn=2075-1729|doi-access=free }}</ref>
* ''Varidnaviria'' is either monophyletic or polyphyletic and may predate the LUCA. The kingdom ''Bamfordvirae'' is likely derived from the other kingdom ''Helvetiavirae'' via [[Fusion gene|fusion]] of two MCPs to have an MCP with two jelly roll folds instead of one. The single jelly roll (SJR) fold MCPs of ''Helvetiavirae'' show a relation to a group of proteins that contain SJR folds, including the [[Cupin superfamily]] and [[nucleoplasmin]]s. Archaeal dsDNA viruses in ''[[Portogloboviridae]]'' contain just one vertical SJR-MCP, which appears to have been duplicated to two for ''Halopanivirales'', so the MCP of ''Portogloboviridae'' likely represents an earlier stage in the evolutionary history of ''Varidnaviria'' MCPs.<ref name=vari /><ref name=krupovic /><ref name=luca /> However, another scenario was later proposed in which the ''Bamfordvirae'' and ''Helvetiavirae'' kingdoms would originate independently suggesting that the ''Bamfordvirae'' DJR-MCP protein snow a relation with the bacterial DUF 2961 protein, leading to a revision of the realm ''Varidnaviria''. It is possible that the ''Bamfordvirae'' DJR-MCP will evolve from this protein independently, however the origin of the DJR-MCP by duplication of the ''Helvetiavirae'' SJR-MCP cannot yet be ruled out.<ref>{{cite journal|vauthors=Krupovic M, Makarova KS, Koonin EV |title=Cellular homologs of the double jelly-roll major capsid proteins clarify the origins of an ancient virus kingdom|journal=Proceedings of the National Academy of Sciences|date=1 February 2022|volume=119|issue=5|doi=10.1073/pnas.2120620119|pmid=35078938 |pmc=8812541 |doi-access=free}}</ref> A molecular phylogenetic analysis suggests that ''Helvetiavirae'' had no involvement in the origin of the ''Bamfordvirae'' DJR-MCP and that they probably derive from the class ''[[Tectiliviricetes]]''.<ref>{{cite journal |vauthors=Woo AC, Gaia M, Guglielmini J, Da Cunha V, Forterre P |title=Phylogeny of the ''Varidnaviria'' Morphogenesis Module: Congruence and Incongruence with the Tree of Life and Viral Taxonomy |journal=Frontiers in Microbiology |volume=12 |article-number=704052 |date=16 July 2021 |page=704052 |doi=10.3389/fmicb.2021.704052 |pmid=34349745 |pmc=8328091|doi-access=free }}</ref>


: Darüber hinaus [[Genetischer Code|kodieren]] ''Bidnaviridae'' für ein [[Rezeptor (Virologie)|rezeptorbindendes]] Protein, das sie von ''[[Reoviridae]]'' (Realm ''[[Riboviria]]'') geerbt haben<ref name="Krupvoic2014"/>
While the realms generally have no genetic relation to each other, there are some exceptions:
* Viruses in the family ''[[Podoviridae]]'' in ''Duplodnaviria'' encode a DNA polymerase that is related to the DNA polymerases encoded by many members of ''Varidnaviria''.<ref name=krupovic2015 />
* Eukaryotic viruses in the kingdom ''[[Shotokuvirae]]'' in ''Monodnaviria'' were created on multiple occasions by recombination events that combined the DNA of ancestral plasmids with complementary DNA (cDNA) of positive sense RNA viruses in ''Riboviria'', by which ssDNA viruses in ''Shotokuvirae'' obtained capsid proteins from RNA viruses.<ref name=mono /><ref name=krupovic />
* The family ''[[Bidnaviridae]]'' in ''Monodnaviria'' was created via integration of a [[Parvoviridae|parvovirus]] (of ''Monodnaviria'') genome into a [[polinton]], a virus-like self-replicating DNA molecule, which are related to viruses in ''Varidnaviria''. Furthermore, bidnaviruses encode a receptor-binding protein inherited from [[Reoviridae|reoviruses]] in the realm ''Riboviria''.<ref>{{cite journal|vauthors=Krupvoic M, Koonin EV|date=18 June 2014|title=Evolution of eukaryotic single-stranded DNA viruses of the Bidnaviridae family from genes of four other groups of widely different viruses|journal=Sci Rep|volume=4|pages=5347|doi=10.1038/srep05347|pmc=4061559|pmid=24939392|bibcode=2014NatSR...4E5347K}}</ref>


Es kam also immer wieder in der Virus-Evolution zu [[Horizontaler Gentransfer|Horizontalem Gentransfer]] zwishen den verschiedenen Realms (ebenso wie zwischen den Viren und ihren zellulären [[Wirt (Biologie)|Wirten]]).
==Subrealm==
In virology, the second highest taxonomy rank established by the ICTV is subrealm, which is the rank below realm. Subrealms of viruses use the suffix -''vira'', viroid subrealms use the suffix -''viroida'', and satellites use the suffix -''satellitida''. The rank below subrealm is kingdom. As of 2019, no taxa are described at the rank of subrealm.<ref name=ictvcode /><ref name=ictv />


== Einzelnachweise ==
==History==
<references>
Prior to the 21st century, it was believed that deep evolutionary relations between viruses could not be discovered due to their high mutation rates and small number of genes making discovering these relations more difficult. Because of this, the highest taxonomic rank for viruses from 1991 to 2017 was order. In the 21st century, however, various methods have been developed that have enabled these deeper evolutionary relationships to be studied, including metagenomics, which has identified many previously unidentified viruses, and comparison of highly conserved traits, leading to the desire to establish higher-level taxonomy for viruses.<ref name=exec />
<ref name="ICTV_nScope" >
{{cite journal |author=[[International Committee on Taxonomy of Viruses]] Executive Committee |date=2020-04-27 |title=The New Scope of Virus Taxonomy: Partitioning the Virosphere Into 15 Hierarchical Ranks |journal=Nat Microbiol |volume=5 |issue=5 |pages=668–674 |doi=10.1038/s41564-020-0709-x |pmc=7186216 |pmid=32341570 |language=en }}
</ref>
<ref name="ICTV_Riboviria" >
{{cite web |author=[[Eugene V. Koonin]], Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn |title=Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria |url=https://ictv.global/ictv/proposals/2019.006G.zip |website=[[International Committee on Taxonomy of Viruses]] (ICTV)|access-date=2020-08-13 |language=en |format=zip:docx |date=2019-10-18 }}
</ref>
<ref name="ICTV_Duplodnaviria" >
{{cite web |author=[[Eugene V. Koonin]], Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn |title=Create a megataxonomic framework, filling all principal/primary taxonomic ranks, for dsDNA viruses encoding HK97-type major capsid proteins |url=https://ictv.global/ictv/proposals/2019.004G.zip |website=[[International Committee on Taxonomy of Viruses]] (ICTV) |access-date=2020-08-13 |language=en |format=zip:docx|date=2019-10-18 }}
</ref>
<ref name="ICTV_Monodnaviria" >
{{cite web |author=[[Eugene V. Koonin]], Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn H|title=Create a megataxonomic framework, filling all principal taxonomic ranks, for ssDNA viruses |url=https://ictv.global/ictv/proposals/2019.005G.zip |website=[[International Committee on Taxonomy of Viruses]] (ICTV) |access-date=2020-08-13 |language=en |format=zip:docx |date=2019-10-18 }}
</ref>
<ref name="ICTV_Varidnaviria" >
{{cite web |author=[[Eugene V. Koonin]], Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn |title=Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria |url=https://ictv.global/ictv/proposals/2019.003G.zip |website=[[International Committee on Taxonomy of Viruses]] (ICTV) |access-date=2020-08-13 |language=en |format=zip:docx |date=2019-10-18 }}
</ref>
<!---------------------------------------->
<ref name="Cervera2016">
{{Cite journal |last1=Cervera |first1=Amelia|last2=Urbina |first2=Denisse |last3=de la Peña|first3=Marcos |date=2016-06-23 |title=Retrozymes are a unique family of non-autonomous retrotransposons with hammerhead ribozymes that propagate in plants through circular RNAs |journal=Genome Biology |volume=17 |issue=1 |pages=135 |doi=10.1186/s13059-016-1002-4 |issn=1474-760X |pmc=4918200 |pmid=27339130 |language=en }}
</ref>
<ref name="McHugh2014">
{{cite journal |author=Colleen A. McHugh, Juan Fontana, Daniel Nemecek, Naiqian Cheng, Anastasia A. Aksyuk, J. Bernard Heymann, Dennis C. Winkler, Alan S. Lam, Joseph S. Wall, Alasdair C. Steven, Egbert Hoiczyk |title=A virus capsid-like nanocompartment that stores iron and protects bacteria from oxidative stress |journal=The EMBO Journal |volume=33 |issue=17 |pages=1896–911 |date=2014-07-14 |pmid=25024436 |pmc=4195785 |doi=10.15252/embj.201488566 |language=en }}
</ref>
<ref name="Kazlauskas2019">
{{cite journal|author=Darius Kazlauskas, Arvind Varsani, [[Eugene V. Koonin]], Mart Krupovic |date=2019-07-31 |title=Multiple Origins of Prokaryotic and Eukaryotic Single-Stranded DNA Viruses From Bacterial and Archaeal Plasmids |journal=[[Nature ]] Communications |volume=10 |issue=1 |pages=3425 |doi=10.1038/s41467-019-11433-0 |pmc=6668415 |pmid=31366885 |bibcode=2019NatCo..10.3425K |language=en }}
</ref>
<ref name="Krupvoic2014">
{{cite journal |author=Mart Krupovic, [[Eugene V. Koonin]] |date=2014-06-18 |title=Evolution of eukaryotic single-stranded DNA viruses of the Bidnaviridae family from genes of four other groups of widely different viruses |journal=Scientific Reports |volume=4 |pages=5347 |doi=10.1038/srep05347 |pmc=4061559 |pmid=24939392 |bibcode=2014NatSR...4E5347K |language=en }}
</ref>
<ref name="Krupovic2015">
{{cite journal |author=Mart Krupovic, [[Eugene V. Koonin]] |date=2015-02 |title=Polintons: a hotbed of eukaryotic virus, transposon and plasmid evolution |journal=[[Nature]] Reviews Microbiology |volume=13 |issue=2 |pages=105–115 |doi=10.1038/nrmicro3389 |pmc=5898198 |pmid=25534808 |language=en }}
</ref>
<ref name="Krupovic2017">
{{cite journal |author=Mart Krupovic, [[Eugene V. Koonin]] |date=2017-03-21 |title=Multiple origins of viral capsid proteins from cellular ancestors |journal=[[PNAS]] |volume=114 |issue=12 |pages=E2401–E2410 |doi=10.1073/pnas.1621061114 |pmc=5373398 |pmid=28265094 |language=en}}
</ref>
<ref name="Krupovic2020">
{{cite journal |author= Mart Krupovic, Valerian V. Dolja, [[Eugene V. Koonin]] |title=The LUCA and its complex virome |journal=[[Nature]] Reviews Microbiology |date=2020-07-04 |volume=18 |issue=11 |pages=661–670 |doi=10.1038/s41579-020-0408-x |pmid=32665595 |language=en <!--|url=https://bpp.oregonstate.edu/sites/agscid7/files/bpp/attachments/lucavirome2020.pdf|access-date=16 August 2020--> |id=[[ResearchGate]]:[https://www.researchgate.net/publication/342933582 342933582] |language=en }}
</ref>
<ref name="Krupovic2022">
{{cite journal |author=Mart Krupovic, Kira S. Makarova, [[Eugene V. Koonin]] |title=Cellular homologs of the double jelly-roll major capsid proteins clarify the origins of an ancient virus kingdom |journal=[[PNAS]] |date=2022-02-01 |volume=119 |issue=5 |doi=10.1073/pnas.2120620119 |pmid=35078938 |pmc=8812541 | id=[[ResearchGate]]:[https://www.researchgate.net/publication/358114247 358114247] |language=en }}
</ref>
<ref name="Lee2022">
{{Cite journal |author=Benjamin D. Lee, [[Eugene V. Koonin]] |date=2022-01-12 |title=Viroids and Viroid-like Circular RNAs: Do They Descend from Primordial Replicators? |journal=MDPI: Life |volume=12 |issue=1 |pages=103 |doi=10.3390/life12010103 |pmid=35054497 |pmc=8781251 |issn=2075-1729 |language=en }}
</ref>
<ref name="Wolf2018">
{{cite journal |author=Yuri I. Wolf, Darius Kazlauskas, Jaime Iranzo, Adriana Lucía-Sanz, Jens H. Kuhn, Mart Krupovic, Valerian V. Dolja, [[Eugene V. Koonin]] |date=2018-11-27 |title=Origins and Evolution of the Global RNA Virome |journal=mBio |volume=9 |issue=6 |pages=e02329-18 |doi=10.1128/mBio.02329-18 |pmc=6282212 |pmid=30482837 |language=en }}
</ref>
<ref name="Woo2021">
Anthony C. Woo, Morgan Gaia, Julien Guglielmini, Violette Da Cunha, [[Patrick Forterre]]: ''Phylogeny of the ''Varidnaviria'' Morphogenesis Module: Congruence and Incongruence with the Tree of Life and Viral Taxonomy.'' In: ''Frontiers in Microbiology'', Band 12, 16. Juli 2021, S.&nbsp;704052, [[doi:10.3389/fmicb.2021.704052]], PMID 34349745, {{PMC|8328091}}, [[ResearchGate]]:[https://www.researchgate.net/publication/353314165 353314165] ({{enS}}).
</ref>
<ref name="Zayed2022">
{{Cite journal |title=Cryptic and abundant marine viruses at the evolutionary origins of Earth's RNA virome |date=2022-04-08 |journal=[[Science]] |volume=376 |issue=6589 |pages=156–162 |author=Ahmed A. Zayed, James M. Wainaina, Guillermo Dominguez-Huerta, Eric Pelletier, Jiarong Guo, Mohamed Mohssen, Funing Tian, Akbar Adjie Pratama, Benjamin Bolduc, Olivier Zablocki, Dylan Cronin, Lindsey Solden, Erwan Delage, Adriana Alberti, Jean-Marc Aury, Quentin Carradec, Corinne Da Silva, Karine Labadie, Julie Poulain, Hans-Joachim Ruscheweyh, Guillem Salazar, Elan Shatoff, Ralf Bundschuh, Kurt Fredrick, Laura S. Kubatko, Samuel Chaffron, Alexander I. Culley, Shinichi Sunagawa, Jens H. Kuhn, Patrick Wincker |doi=10.1126/science.abm5847 |pmid=35389782 |bibcode=2022Sci...376..156Z |id=[[ResearchGate]]:[https://www.researchgate.net/publication/359802266 359802266] |language=en }} Siehe insbes. [https://www.science.org/cms/10.1126/science.abm5847/asset/ac3670a9-8d0f-4f80-ac94-5cfb4833d45b/assets/images/large/science.abm5847-f3.jpg Fig.&nbsp;3]. Dazu:
* Emily Caldwell: [https://news.osu.edu/ocean-water-samples-yield-treasure-trove-of-rna-virus-data/ Ocean water samples yield treasure trove of RNA virus data]. Pressemitteilung der [[Ohio State University]] (OSU) vom 7. April 2022.<!--
* [https://www.sciencedaily.com/releases/2022/04/220407141837.htm Ocean water samples yield treasure trove of RNA virus data – Study of organisms in the sea identifies 5,500 new species]. Auf: [[Science News]] vom 7. April 2022. Quelle: Ohio State University.
* [https://scitechdaily.com/5500-new-rna-virus-species-discovered-in-the-ocean-tracing-the-origins-of-viruses-and-the-origins-of-life/ 5,500 New RNA Virus Species Discovered in the Ocean – Tracing the Origins of Viruses and the Origins of Life]. Auf: [[SciTechDaily]] vom 9. April 2022.
* Guillermo Dominguez Huerta ''et&nbsp;al.'': ''[https://www.sciencealert.com/more-than-5-000-brand-new-viruses-have-been-discovered-lurking-in-the-oceans Over 5,000 Previously Unknown Viruses Have Been Discovered Lurking in The Oceans].'' Auf: ''science<sup>alert</sup>'' vom 8. April 2022. Quelle: The Conversation.-->
* Nadja Podbregar: [https://www.scinexx.de/news/biowissen/stammbaum-der-rna-viren-verdoppelt-sich/ Stammbaum der RNA-Viren verdoppelt sich]. Auf: ''[[scinexx]].de'' vom 8. April 2022.
</ref>
</references>


[[Kategorie:Viren, Viroide und Prionen]]
In two votes in 2018 and 2019, the ICTV agreed to adopt a 15-rank classification system for viruses, ranging from realm to species.<ref name=exec /> ''Riboviria'' was established in 2018 based on phylogenetic analysis of the RNA-dependent polymerases being monophyletic,<ref name=ribo /><ref>{{cite web|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=201907095|title=ICTV Taxonomy history: ''Riboviria''|author=<!--Not stated-->|date=February 2019|website=International Committee on Taxonomy of Viruses|publisher=International Committee on Taxonomy of Viruses|access-date=13 August 2020}}</ref> ''Duplodnaviria'' was established in 2019 based on increasing evidence that tailed bacteriophages and herpesviruses shared many traits,<ref name=duplo /><ref>{{cite web|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=201907117|title=ICTV Taxonomy history: ''Duplodnaviria''|author=<!--Not stated-->|date=March 2020|website=International Committee on Taxonomy of Viruses|publisher=International Committee on Taxonomy of Viruses|access-date=13 August 2020}}</ref> ''Monodnaviria'' was established in 2019 after the relation and origin of CRESS-DNA viruses was resolved,<ref name=mono /><ref>{{cite web|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=201907161|title=ICTV Taxonomy history: ''Monodnaviria''|author=<!--Not stated-->|date=March 2020|website=International Committee on Taxonomy of Viruses|publisher=International Committee on Taxonomy of Viruses|access-date=13 August 2020}}</ref> and ''Varidnaviria'' was established 2019 based on the shared characteristics of member viruses.<ref name=vari /><ref>{{cite web|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=201908702|title=ICTV Taxonomy history: ''Varidnaviria''|author=<!--Not stated-->|date=March 2020|website=International Committee on Taxonomy of Viruses|publisher=International Committee on Taxonomy of Viruses|access-date=13 August 2020}}</ref>
[[Kategorie:Evolution]]

==See also==
* [[Virus classification]]
*[[Minerals]]

==References==
{{Reflist}}

==Further reading==
* {{Cite journal|last=Ward|first=C. W.|date=1993|title=Progress towards a higher taxonomy of viruses|journal=Research in Virology|volume=144|issue=6|pages=419–53|doi=10.1016/S0923-2516(06)80059-2|pmid=8140287|pmc=7135741}}

{{Taxonomic ranks}}

[[Category:Virus taxonomy]]
[[Category:Virus realms| ]]

Version vom 27. Dezember 2023, 20:59 Uhr

Im Gegensatz zu den drei Domänen der zellulären Organismen - Archaea, Bacteria und Eukarya (Archaeen, Bakterien und Eukaryoten – komplex-zellulären Organismen), die einen gemeinsamen Vorfahren (Urvorfahren) haben, besteht zwischen den Virus-Realms im Allgemeinen keine genetische Beziehung, die auf gemeinsamer Abstammung beruht. Selbst innerhalb der einzelnen Realms stammen die Mitglieder nicht unbedingt von einem gemeinsamen Vorfahren ab. Die Realms sind so definiert (charakterisiert), dass sie Gruppen von Viren auf der Grundlage hochkonservierter Merkmale zusammenfassen, d. h. nicht auf der Grundlage einer gemeinsamen Abstammung, wie sie als Grundlage für die Taxonomie des zellulären Lebens dient. Jeder Realm der Viren stellt daher mindestens eine Instanz der Entstehung von Viren dar.[1] Im einzelnen:

Adnaviria

Der Ursprung der Archaeen parasitierenden Adnaviria ist unbekannt (Stand 2020). Es wird aber vermutet, dass Vertreter der Adnaviria schon seit langer Zeit existieren, und dass sie bereits den letzten gemeinsamen Vorfahren der (heutigen) Archaeen (englisch last archaeal common ancestor, LACA) infiziert haben könnten.[2]

Duplodnaviria

Der Realm Duplodnaviria ist entweder monophyletisch oder polyphyletisch. Er geht möglicherweise sogar dem letzten „universellen“ gemeinsamen Ahn der heutigen zellulären Organismen (englisch last universal common ancestor, LUCA, auch most recent common ancestor, MRCA) voraus. Der genaue Ursprung des Realms ist nicht bekannt. Von allen Mitgliedern wird ein Hauptkapsidprotein (MCP) mit einer Faltung wie bei Escherichia-Virus HK97 (wissenschaftlich Byrnievirus HK97) kodiert und daher als HK97-MCP bezeichnet. Diese Proteinfaltung kommt außerhalb des Realms nur bei der Proteinfamilie der Encapsuline bei Bakterien und Archaeen vor, wie es Nanokompartimente ausbildet, die Ferritin-artige Proteine und Peroxidasen einkapseln, die vor oxidativem Stress schützen.[3][4] Die Beziehung zwischen den Duplodnaviria und diesen Nanokompartimenten ist noch nicht vollständig verstanden (Stand 2020).[5][6][2]

Monodnaviria

Der Realm Monodnaviria ist polyphyletisch, er scheint sich mehrfach aus zirkulären Plasmiden von Bakterien und Archaeen entwickelt zu haben. Das sind DNA-Moleküle außerhalb des Archaeen- bzw. Bakterienchromosoms, die sich im Innern dieser Archaeen bzw. Bakterien selbst replizieren.[7][8]

Riboviria

Der Realm Riboviria ist entweder monophyletisch oder polyphyletisch.

Die Reverse Transkriptase (RT) im Virusreich Pararnavirae hat sich wahrscheinlich bei einer einzigen Gelegenheit aus einem Retrotransposon entwickelt (einer Art von selbstreplizierendem DNA-Molekül, das sich durch reverse Transkription repliziert.

Der Ursprung der RNA-abhängigen RNA-Polymerase (RdRp) im Virusreich Orthornavirae ist weniger sicher. Es es wurde einerseits vermutet, dass die RdRP entweder von einem bakteriellen Intron der Gruppe II abstammen, das für Reverse Transkriptase (RT) kodiert. Sie könnte aber auch bereits vor dem letzten „universellen“ gemeinsamen Ahn der heutigen zellulären Organismen (LUCA) entstanden sein, wenn dieser Nachkomme von Ribozyten einer urzeitlichen RNA-Welt war. Die Orthornavirae könnten dann den RT des heutigen zellulären Lebens mit DNA-Genom vorausgehen.[9][10][2] Eine größere Studie aus dem Jahr 2022, in der neue Viren-Phyla beschrieben wurden, legt die Annahme nahe, dass RNA-Viren von der RNA-Welt abstammen. Die Retroelemente der heutigen zellulären Organismen könnten dann von einem Vorfahren abstammen, der mit dem Phylum Lenarviricota verwandt ist; Mitglieder eines neu entdeckten Orthornavirae-Phylums (vorgeschlagene Bezeichnung „Taraviricota“) sollten danach die Vorfahren aller RNA-Viren sein.[11]

Ribozyviria

Der Ursprung des realms Ribozyviria ist unbekannt. Es wurde vorgeschlagen, dass sie sich von Retrozymen (einer Familie von Retrotransposons[12]) oder einem viroidähnlichen Element (d. h. einem Viroid oder Satellit) durch Einfanhg eines Kapsidprotein ableiten könnten.[13]

Varidnaviria

Der Realm Varidnaviria ist entweder monophyletisch oder polyphyletisch und geht möglicherweise (ebenfalls) dem letzten universellen gemeinsamen Ahn (LUCA) der heutigen zellulären Organismen voraus. Das Virenreich Bamfordvirae ist wahrscheinlich aus dem anderen Reich Helvetiavirae durch Verschmelzung zweier Hauptkapsidproteine (MCPs) entstanden, so dass es als Ergebnis nun ein einziges MCP mit zwei Jelly-Roll-Faltungen (double jelly roll, DJR) anstelle von einer gibt. Die (vermutlich ursprünglichen) MCPs der Helvetiavirae mit einer einzigen Jelly-Roll-Faltung (single jelly roll, SJR) stehen in Beziehung zu einer Gruppe von Proteinen, die die ebenfalls SJR-Faltungen enthalten, darunter die Cupin-Superfamilie[14] und die Nukleoplasmine.[15]

Die Archaeen parasitierenden dsDNA-Viren der Familie Portogloboviridae (bisher keinem Realm sicher zugeodnet) enthalten nur ein vertikales SJR-MCP, das bei den Halopanivirales (Helvetiavirae) anscheinend verdoppelt wurde, so dass das MCP der Portogloboviridae wahrscheinlich eine frühere Stufe in der Evolutionsgeschichte der Varidnaviria-MCPs darstellt.[16][6][2]

Später (2021/2022) wurde jedoch ein anderes Szenario vorgeschlagen, bei dem die beiden Reiche Bamfordvirae und Helvetiavirae unabhängig voneinander entstanden sind. Dies wierd unterstützt durch die Beobachtung, dass das DJR-MCP-Protein der Bamfordvirae mit dem bakteriellen Protein DUF 2961.[17][18] verwandt ist, was zu einer Reorganisation des Reiches Varidnaviria führen könnte. Eine molekularphylogenetische Analyse legt nahe, dass die Helvetiavirae nicht an der Entstehung des DJR-MCP der Bamfordvirae beteiligt waren und dass sie wahrscheinlich aus der Klasse Tectiliviricetes (Phylum Preplasmiviricota der Bamfordvirae) stammen.[19]

Es ist also möglich, dass sich das DJR-MCP der Bamfordvirae unabhängig von diesem Protein entwickelt hat, aber die Entstehung des DJR-MCP durch Duplikation des SJR-MCP der Helvetiavirae kann derzeit (2022) noch nicht ausgeschlossen werden.[20]

Genetische Beziehungen zwischen den Virus-Realms

Obwohl die Realms im Allgemeinen keine genetische Beziehung zueinander haben, gibt es einige Ausnahmen:

Darüber hinaus kodieren Bidnaviridae für ein rezeptorbindendes Protein, das sie von Reoviridae (Realm Riboviria) geerbt haben[22]

Es kam also immer wieder in der Virus-Evolution zu Horizontalem Gentransfer zwishen den verschiedenen Realms (ebenso wie zwischen den Viren und ihren zellulären Wirten).

Einzelnachweise

  1. ↑ International Committee on Taxonomy of Viruses Executive Committee: The New Scope of Virus Taxonomy: Partitioning the Virosphere Into 15 Hierarchical Ranks. In: Nat Microbiol. 5. Jahrgang, Nr. 5, 27. April 2020, S. 668–674, doi:10.1038/s41564-020-0709-x, PMID 32341570, PMC 7186216 (freier Volltext) – (englisch).
  2. ↑ a b c d Mart Krupovic, Valerian V. Dolja, Eugene V. Koonin: The LUCA and its complex virome. In: Nature Reviews Microbiology. 18. Jahrgang, Nr. 11, 4. Juli 2020, ResearchGate:342933582, S. 661–670, doi:10.1038/s41579-020-0408-x, PMID 32665595 (englisch).
  3. ↑ Colleen A. McHugh, Juan Fontana, Daniel Nemecek, Naiqian Cheng, Anastasia A. Aksyuk, J. Bernard Heymann, Dennis C. Winkler, Alan S. Lam, Joseph S. Wall, Alasdair C. Steven, Egbert Hoiczyk: A virus capsid-like nanocompartment that stores iron and protects bacteria from oxidative stress. In: The EMBO Journal. 33. Jahrgang, Nr. 17, 14. Juli 2014, S. 1896–911, doi:10.15252/embj.201488566, PMID 25024436, PMC 4195785 (freier Volltext) – (englisch).
  4. ↑ Pfam PF04454 Encapsulating protein for peroxidase: Linocin_M18.
  5. ↑ Eugene V. Koonin, Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn: Create a megataxonomic framework, filling all principal/primary taxonomic ranks, for dsDNA viruses encoding HK97-type major capsid proteins. (zip:docx) In: International Committee on Taxonomy of Viruses (ICTV). 18. Oktober 2019, abgerufen am 13. August 2020 (englisch).
  6. ↑ a b c Mart Krupovic, Eugene V. Koonin: Multiple origins of viral capsid proteins from cellular ancestors. In: PNAS. 114. Jahrgang, Nr. 12, 21. März 2017, S. E2401–E2410, doi:10.1073/pnas.1621061114, PMID 28265094, PMC 5373398 (freier Volltext) – (englisch).
  7. ↑ a b Eugene V. Koonin, Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn H: Create a megataxonomic framework, filling all principal taxonomic ranks, for ssDNA viruses. (zip:docx) In: International Committee on Taxonomy of Viruses (ICTV). 18. Oktober 2019, abgerufen am 13. August 2020 (englisch).
  8. ↑ Darius Kazlauskas, Arvind Varsani, Eugene V. Koonin, Mart Krupovic: Multiple Origins of Prokaryotic and Eukaryotic Single-Stranded DNA Viruses From Bacterial and Archaeal Plasmids. In: Nature Communications. 10. Jahrgang, Nr. 1, 31. Juli 2019, S. 3425, doi:10.1038/s41467-019-11433-0, PMID 31366885, PMC 6668415 (freier Volltext), bibcode:2019NatCo..10.3425K (englisch).
  9. ↑ Eugene V. Koonin, Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn: Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria. (zip:docx) In: International Committee on Taxonomy of Viruses (ICTV). 18. Oktober 2019, abgerufen am 13. August 2020 (englisch).
  10. ↑ Yuri I. Wolf, Darius Kazlauskas, Jaime Iranzo, Adriana Lucía-Sanz, Jens H. Kuhn, Mart Krupovic, Valerian V. Dolja, Eugene V. Koonin: Origins and Evolution of the Global RNA Virome. In: mBio. 9. Jahrgang, Nr. 6, 27. November 2018, S. e02329–18, doi:10.1128/mBio.02329-18, PMID 30482837, PMC 6282212 (freier Volltext) – (englisch).
  11. ↑ Ahmed A. Zayed, James M. Wainaina, Guillermo Dominguez-Huerta, Eric Pelletier, Jiarong Guo, Mohamed Mohssen, Funing Tian, Akbar Adjie Pratama, Benjamin Bolduc, Olivier Zablocki, Dylan Cronin, Lindsey Solden, Erwan Delage, Adriana Alberti, Jean-Marc Aury, Quentin Carradec, Corinne Da Silva, Karine Labadie, Julie Poulain, Hans-Joachim Ruscheweyh, Guillem Salazar, Elan Shatoff, Ralf Bundschuh, Kurt Fredrick, Laura S. Kubatko, Samuel Chaffron, Alexander I. Culley, Shinichi Sunagawa, Jens H. Kuhn, Patrick Wincker: Cryptic and abundant marine viruses at the evolutionary origins of Earth's RNA virome. In: Science. 376. Jahrgang, Nr. 6589, 8. April 2022, ResearchGate:359802266, S. 156–162, doi:10.1126/science.abm5847, PMID 35389782, bibcode:2022Sci...376..156Z (englisch). Siehe insbes. Fig. 3. Dazu:
  12. ↑ Amelia Cervera, Denisse Urbina, Marcos de la Peña: Retrozymes are a unique family of non-autonomous retrotransposons with hammerhead ribozymes that propagate in plants through circular RNAs. In: Genome Biology. 17. Jahrgang, Nr. 1, 23. Juni 2016, ISSN 1474-760X, S. 135, doi:10.1186/s13059-016-1002-4, PMID 27339130, PMC 4918200 (freier Volltext) – (englisch).
  13. ↑ Benjamin D. Lee, Eugene V. Koonin: Viroids and Viroid-like Circular RNAs: Do They Descend from Primordial Replicators? In: MDPI: Life. 12. Jahrgang, Nr. 1, 12. Januar 2022, ISSN 2075-1729, S. 103, doi:10.3390/life12010103, PMID 35054497, PMC 8781251 (freier Volltext) – (englisch).
  14. ↑ Pfam PF00190 Cupin.
  15. ↑ InterPro: F IPR004301 Nucleoplasmin family.
  16. ↑ Eugene V. Koonin, Valerian V. Dolja, Mart Krupovic, Arvind Varsani, Yuri I. Wolf, M. Zerbini, Jens H. Kuhn: Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria. (zip:docx) In: International Committee on Taxonomy of Viruses (ICTV). 18. Oktober 2019, abgerufen am 13. August 2020 (englisch).
  17. ↑ DUF2961 domain-containing protein. Auf: PropLec.
  18. ↑ NCBI Protein: DUF2961 domain-containing protein [Catellatospora sichuanensis] NCBI Reference Sequence: WP_144127294.1.
  19. ↑ Anthony C. Woo, Morgan Gaia, Julien Guglielmini, Violette Da Cunha, Patrick Forterre: Phylogeny of the Varidnaviria Morphogenesis Module: Congruence and Incongruence with the Tree of Life and Viral Taxonomy. In: Frontiers in Microbiology, Band 12, 16. Juli 2021, S. 704052, doi:10.3389/fmicb.2021.704052, PMID 34349745, PMC 8328091 (freier Volltext), ResearchGate:353314165 (englisch).
  20. ↑ Mart Krupovic, Kira S. Makarova, Eugene V. Koonin: Cellular homologs of the double jelly-roll major capsid proteins clarify the origins of an ancient virus kingdom. In: PNAS. 119. Jahrgang, Nr. 5, 1. Februar 2022, ResearchGate:358114247, doi:10.1073/pnas.2120620119, PMID 35078938, PMC 8812541 (freier Volltext) – (englisch).
  21. ↑ Mart Krupovic, Eugene V. Koonin: Polintons: a hotbed of eukaryotic virus, transposon and plasmid evolution. In: Nature Reviews Microbiology. 13. Jahrgang, Nr. 2, Februar 2015, S. 105–115, doi:10.1038/nrmicro3389, PMID 25534808, PMC 5898198 (freier Volltext) – (englisch).
  22. ↑ Mart Krupovic, Eugene V. Koonin: Evolution of eukaryotic single-stranded DNA viruses of the Bidnaviridae family from genes of four other groups of widely different viruses. In: Scientific Reports. 4. Jahrgang, 18. Juni 2014, S. 5347, doi:10.1038/srep05347, PMID 24939392, PMC 4061559 (freier Volltext), bibcode:2014NatSR...4E5347K (englisch).
Abgerufen von „https://de.wikipedia.org/w/index.php?title=Ursprünge_der_Viren&oldid=240578038“