Editing Symbiogenesis (section)

== History ==

[[File:Konstantin Mereschkowski Symbiogenesis Tree of Life.jpg|thumb|upright=1.5 |[[Konstantin Mereschkowski]]'s 1905 [[Tree of life (biology)|tree-of-life]] diagram, showing the origin of complex life-forms by two episodes of symbiogenesis, the incorporation of [[symbiosis|symbiotic]] [[bacteria]] to form successively [[nucleus (cell)|nuclei]] and [[chloroplast]]s<ref name="SciAmMereschkowsky">{{cite magazine |title=Mereschkowsky's Tree of Life |url=https://www.scientificamerican.com/article/mereschkowskys-tree-of-li/# |magazine=[[Scientific American]] |access-date=1 May 2017}}</ref>]]

The [[Russians|Russian]] botanist [[Konstantin Mereschkowski]] first outlined the theory of symbiogenesis (from [[Ancient Greek|Greek]]: σύν ''syn'' "together", βίος ''bios'' "life", and γένεσις ''genesis'' "origin, birth") in his 1905 work, ''The nature and origins of chromatophores in the plant kingdom'', and then elaborated it in his 1910 ''The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study of the Origins of Organisms''.<ref>{{cite journal |last=Mereschkowski |first=Konstantin |author-link=Konstantin Mereschkowski |title=Über Natur und Ursprung der Chromatophoren im Pflanzenreiche |trans-title=On the nature and origin of chromatophores in the plant kingdom |journal=Biologisches Centralblatt |date=15 September 1905 |volume=25 |issue=18 |pages=593–604 |language=de |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822009245838;view=1up;seq=603}}</ref><ref>See:
* {{cite journal |last=Mereschkowski |first=Konstantin |title=Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer neuen Lehre von der Entstehung der Organismen |journal=Biologisches Centralblatt |date=15 April 1910 |volume=30 |issue=8 |pages=278–288 |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822009245903;view=1up;seq=292 |trans-title=Theory of two types of plasms as the basis of symbiogenesis, a new study of the origin of organisms [part 1 of 4] |language=de |ref=none}}
* {{cite journal |last=Mereschkowsky |first=Konstantin |title=Theorie der zwei Plasmaarten als Grundlage der Symbogenesis, einer neuen Lehre von der Entstehung der Organismen |journal=Biologisches Centralblatt |date=1 May 1910 |volume=30 |issue=9 |pages=289–303 |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822009245903;view=1up;seq=303 |trans-title=Theory of two types of plasms as the basis of symbiogenesis, a new study of the origin of organisms [part 2 of 4] |language=de |ref=none}}
* {{cite journal |last=Mereschkowski |first=Konstantin |title=Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer neuen Lehre von der Entstehung der Organismen |journal=Biologisches Centralblatt |date=15 May 1910 |volume=30 |issue=10 |pages=321–347 |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822009245903;view=1up;seq=335 |trans-title=Theory of two types of plasms as the basis of symbiogenesis, a new study of the origin of organisms [part 3 of 4] |language=de |ref=none}}
* {{cite journal |last=Mereschkowsky |first=Konstantin |title=Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer neuen Lehre von der Entstehung der Organismen |trans-title=Theory of two types of plasms as the basis of symbiogenesis, a new study of the origin of organisms [part 4 of 4] |journal=Biologisches Centralblatt |date=1 June 1910 |volume=30 |issue=11 |pages=353–367 |language=de |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822009245903;view=1up;seq=367 |ref=none}}</ref><ref name="Martin">{{cite journal |last1=Martin |first1=William F. |author1-link=William F. Martin |last2=Roettger |first2=Mayo |last3=Kloesges |first3=Thorsten |last4=Thiergart |first4=Thorsten |last5=Woehle |first5=Christian |last6=Gould |first6=Sven |last7=Dagan |first7=Tal |display-authors=3 |title=Modern endosymbiotic theory: Getting lateral gene transfer into the equation |url=http://www.molevol.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/Molekulare_Evolution/Dokumente/martin001.pdf |url-status=dead |journal=Journal of Endocytobiosis and Cell Research |volume=23 |pages=1–5 |archive-url=https://web.archive.org/web/20220309044351/https://www.molevol.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/Molekulare_Evolution/Dokumente/martin001.pdf |archive-date=2022-03-09 |access-date=2015-07-20}}(journal URL: [http://www.molevol.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/Molekulare_Evolution/Dokumente/martin001.pdf] {{Webarchive|url=https://web.archive.org/web/20220309044351/https://www.molevol.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/Molekulare_Evolution/Dokumente/martin001.pdf|date=2022-03-09}})</ref> Mereschkowski proposed that complex life-forms had originated by two episodes of symbiogenesis, the incorporation of [[symbiosis|symbiotic]] [[bacteria]] to form successively [[nucleus (cell)|nuclei]] and [[chloroplast]]s.<ref name="SciAmMereschkowsky"/> Mereschkowski knew of the work of botanist [[Andreas Franz Wilhelm Schimper|Andreas Schimper]]. In 1883, Schimper had observed that the division of [[chloroplast]]s in green plants closely resembled that of free-living [[cyanobacteria]]. Schimper had tentatively proposed (in a footnote) that green plants had arisen from a [[mutualism (biology)|symbiotic]] union of two organisms.<ref>See:
* {{cite journal |last=Schimper |first=A. F. W. |title=Ueber die Entwicklung der Chlorophyllkörner und Farbkörper |journal=Botanische Zeitung |date=16 February 1883 |volume=41 |issue=7 |pages=105–114 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044106391576;view=1up;seq=91 |trans-title=On the development of chlorophyll granules and colored bodies [part 1 of 4] |language=de |ref=none}} From p. 105: ''"Inzwischen theilte mir Herr Professor Schmitz mit, dass … die höheren Pflanzen sich ebenso verhalten würden."'' (Meanwhile, Prof. Schmitz reported to me that among algae, the creation of chlorophyll granules from the cell plasm doesn't occur, but that they arise exclusively from one another by division. The spores receive from the mother plant chlorophyll granules, which create, by division, all of the chlorophyll granules of the plants that arises from them [i.e., the spores]. This finding in algae made it seem likely to Prof. Schmitz that the higher plants would behave likewise.) From p. 106: ''"Meine Untersuchungen haben ergeben, … aus dem Scheitelmeristem sich entwickelnden Gewebe erzeugen."'' (My investigations have revealed that the vegetation points [i.e., points of vegetative growth] always contain differentiated chlorophyll bodies or their colorless rudiments; that they arise not by creation from the cell plasm, but from one another by division, and that they create all chlorophyll bodies and starch-forming [bodies] of the tissues developing from the apical meristem.) From p. 112, footnote 2: ''"Sollte es sich definitiv bestätigen, … an eine Symbiose erinnern."'' (If it should definitely be confirmed that the plastids in egg cells are not formed anew, then their relation to the organism containing them would somewhat suggest a symbiosis.)
* {{cite journal |last=Schimper |first=A. F. W. |title=Ueber die Entwicklung der Chlorophyllkörner und Farbkörper |journal=Botanische Zeitung |date=23 February 1883 |volume=41 |issue=8 |pages=121–131 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044106391576;view=1up;seq=99 |trans-title=On the development of chlorophyll granules and colored bodies [part 2 of 4] |language=de |ref=none}}
* {{cite journal |last=Schimper |first=A. F. W. |title=Ueber die Entwicklung der Chlorophyllkörner und Farbkörper |journal=Botanische Zeitung |date=2 March 1883 |volume=41 |issue=9 |pages=137–146 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044106391576;view=1up;seq=107 |trans-title=On the development of chlorophyll granules and colored bodies [part 3 of 4] |language=de |ref=none}}
* {{cite journal |last=Schimper |first=A. F. W. |title=Ueber die Entwicklung der Chlorophyllkörner und Farbkörper |journal=Botanische Zeitung |date=9 March 1883 |volume=41 |issue=10 |pages=153–162 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044106391576;view=1up;seq=115 |trans-title=On the development of chlorophyll granules and colored bodies [part 4 of 4] |language=de |ref=none}}</ref> In 1918 the French scientist [[Paul Portier (physiologist)|Paul Jules Portier]] published ''Les Symbiotes'', in which he claimed that the [[mitochondria]] originated from a symbiosis process.<ref>{{cite book |last=Portier |first=Paul |title=Les Symbiotes |date=1918 |publisher=Masson et Cie. |location=Paris, France |page=293 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015011399261;view=1up;seq=325 |language=fr}} From p. 293: ''"Cette modification dans les rapports des appareils nucléaire et mitochondrial peut être le résultat de deux mécanismes. … Cette la ''parthénogénèse''."'' (This modification in the relations of the nuclear and mitochondrial systems could be the result of two mechanisms: (a) There is a combination of two factors: contribution of new symbionts by the spermatozoid and reduction division. That is ''fertilization''. (b) A single factor exists: reduction division: in this case, the egg contains sufficiently active symbionts. That is ''parthenogenesis''.)</ref><ref name="Lane">{{cite book |last=Lane |first=Nick |author-link=Nick Lane |title=Power, Sex, Suicide. Mitochondria and the Meaning of Life |url=https://archive.org/details/powersexsuicidem0000lane |url-access=registration |date=2005 |publisher=[[Oxford University Press]] |location=New York |isbn=9780199205646 |page=[https://archive.org/details/powersexsuicidem0000lane/page/14 14]}}</ref> [[Ivan Wallin]] advocated the idea of an endosymbiotic origin of [[mitochondrion|mitochondria]] in the 1920s.<ref>{{cite journal |last=Wallin |first=Ivan E. |author-link=Ivan Wallin |title=The Mitochondria Problem |journal=The American Naturalist |year=1923 |volume=57 |issue=650 |pages=255–61 |doi=10.1086/279919|bibcode=1923ANat...57..255W |s2cid=85144224 }}</ref><ref name="WallinBk">{{cite book |last=Wallin |first=Ivan E. |author-link=Ivan Wallin |title=Symbionticism and the origin of species |year=1927 |publisher=[[Williams & Wilkins]] |location=Baltimore |pages=117 |url=https://archive.org/stream/symbionticismori00wall#page/116/mode/2up}}</ref>
The Russian botanist [[Boris Kozo-Polyansky]] became the first to explain the theory in terms of [[Darwinian evolution]].<ref>{{cite journal |last=Margulis |first=Lynn |author-link=Lynn Margulis |title=Symbiogenesis. A new principle of evolution rediscovery of Boris Mikhaylovich Kozo-Polyansky (1890–1957) |journal=Paleontological Journal |year=2011 |volume=44 |issue=12 |pages=1525–1539 |doi=10.1134/S0031030110120087|s2cid=86279772 |url=https://works.bepress.com/cgi/viewcontent.cgi?article=1019&context=lynn_margulis }}</ref> In his 1924 book ''A New Principle of Biology. Essay on the Theory of Symbiogenesis'',<ref>{{cite book |last=Kozo-Polyansky |first=Boris Mikhaylovich |title=Новый принцип биологии. Очерк теории симбиогенеза |trans-title=A New Principle of Biology. Essay on the Theory of Symbiogenesis |date=1924 |publisher=Пучина (Puchina) |location=Moscow and Leningrad (St. Petersburg), Russia |language=ru}}
* English translation: {{cite book |last1=Kozo-Polyansky |first1=Boris Mikhaylovich |translator-last=Fet |translator-first=Victor |editor-last=Margulis |editor-first=Lynn |title=Symbiogenesis: A New Principle of Evolution |date=2010 |publisher=[[Harvard University Press]] |location=Cambridge, Massachusetts |ref=none}}
* Reviewed in: {{cite journal |last1=Niklas |first1=Karl J. |title=Boris M. Kozo-Polyansky, Symbiogenesis: A New Principle of Evolution |journal=Symbiosis |date=2010 |volume=52 |issue=1 |pages=49–50 |doi=10.1007/s13199-010-0098-7|bibcode=2010Symbi..52...49N |s2cid=41635248  |ref=none}}</ref> he wrote, "The theory of symbiogenesis is a theory of selection relying on the phenomenon of symbiosis."<ref>{{cite book |last1=Corning |first1=Peter A. |title=Holistic Darwinism: Synergy, Cybernetics, and the Bioeconomics of Evolution |year=2010 |publisher=[[University of Chicago Press]] |location=Chicago |isbn=978-0-22611-633-4 |page=81 |url=https://books.google.com/books?id=NDeW4UNRmkwC}}</ref> 

These theories did not gain traction until more detailed electron-microscopic comparisons between cyanobacteria and chloroplasts were made, such as by [[Hans Ris]] in 1961 and 1962.<ref>{{cite journal |last1=Ris |first1=Hans |last2=Plaut |first2=Walter |title=Ultrastructure of DNA-containing areas in the chloroplast of Chlamydomonas |journal=The Journal of Cell Biology |volume=13 |issue=3 |pages=383–91 |date=June 1962 |pmid=14492436 |pmc=2106071 |doi=10.1083/jcb.13.3.383 }}</ref><ref>{{cite journal |last1=Ris |first1=Hans |last2=Singh |first2=R. N. |title=Electron microscope studies on blue-green algae |journal=The Journal of Biophysical and Biochemical Cytology |volume=9 |issue=1 |pages=63–80 |date=January 1961 |pmid=13741827 |pmc=2224983 |doi=10.1083/jcb.9.1.63 }}</ref> These, combined with the discovery that plastids and mitochondria contain their own DNA,<ref>{{cite journal |last1=Stocking |first1=C. |last2=Gifford |first2=E. |title=Incorporation of thymidine into chloroplasts of ''Spirogyra'' |journal=Biochem. Biophys. Res. Commun. |year=1959 |volume=1 |issue=3 |pages =159–64 |doi=10.1016/0006-291X(59)90010-5}}</ref> led to a resurrection of the idea of symbiogenesis in the 1960s.
[[Lynn Margulis]] advanced and substantiated the theory with microbiological evidence in a 1967 paper, ''On the origin of mitosing cells.''<ref>{{cite journal |last=Sagan |first=Lynn |title=On the origin of mitosing cells |journal=Journal of Theoretical Biology |volume=14 |issue=3 |pages=255–74 |date=March 1967 |pmid=11541392 |doi=10.1016/0022-5193(67)90079-3 |bibcode=1967JThBi..14..225S |author-link=Lynn Margulis }}</ref> In her 1981 work ''Symbiosis in Cell Evolution'' she argued that eukaryotic cells originated as communities of interacting entities, including endosymbiotic [[spirochaete]]s that developed into eukaryotic [[flagellum|flagella]] and [[cilium|cilia]]. This last idea has not received much acceptance, because flagella lack DNA and do not show ultrastructural similarities to [[bacteria]] or to [[archaea]] (see also: [[Evolution of flagella]] and [[Prokaryotic cytoskeleton]]). According to Margulis and [[Dorion Sagan]],<ref>{{cite book |last1=Margulis |first1=Lynn |author-link=Lynn Margulis |last2=Sagan |first2=Dorion |author2-link=Dorion Sagan |title=Microcosmos: Four Billion Years of Microbial Evolution |year=1997 |publisher=[[University of California Press]] |location=Berkeley, Los Angeles, London |isbn=0-520-21064-6 |page=29 |url=https://books.google.com/books?id=eo_sMMRxgAUC}}</ref> "Life did not take over the globe by combat, but by networking" (i.e., by cooperation). [[Christian de Duve]] proposed that the [[peroxisome]]s may have been the first endosymbionts, allowing cells to withstand growing amounts of free molecular oxygen in the Earth's atmosphere. However, it now appears that peroxisomes may be formed [[De novo synthesis|''de novo'']], contradicting the idea that they have a symbiotic origin.<ref name="Gabaldón Snel Zimmeren Hemrika p. ">{{cite journal |last1=Gabaldón |first1=Toni |last2=Snel |first2=Berend |last3=Zimmeren |first3=Frank van |last4=Hemrika |first4=Wieger |last5=Tabak |first5=Henk |last6=Huynen |first6=Martijn A. |display-authors=3 |title=Origin and evolution of the peroxisomal proteome |journal=Biology Direct |volume=1 |issue=1 |date=23 March 2006 |page=8 |doi=10.1186/1745-6150-1-8 |pmid=16556314 |pmc=1472686 |doi-access=free }}
(Provides evidence that contradicts an endosymbiotic origin of peroxisomes, and suggests instead that they originate evolutionarily from the [[endoplasmic reticulum]])</ref> The fundamental theory of symbiogenesis as the origin of mitochondria and chloroplasts is now widely accepted.<ref name=":1">{{Cite journal |last=Cornish-Bowden |first=Athel |title=Lynn Margulis and the origin of the eukaryotes |journal=[[Journal of Theoretical Biology]] |series=The origin of mitosing cells: 50th anniversary of a classic paper by Lynn Sagan (Margulis) |date=7 December 2017 |volume=434 |page=1 |doi=10.1016/j.jtbi.2017.09.027 |pmid=28992902 |bibcode=2017JThBi.434....1C |url=https://www.sciencedirect.com/science/article/pii/S0022519317304459 }}</ref>

Symbiogenesis revolutionized the history of evolution by proposing a mechanism for evolutionary development not encompassed in the original Darwininan vision. Symbiogenesis demonstrated that major evolutionary advancements, particularly the origin of eukaryotic cells, may have resulted from symbiotic mergers rather than from gradual mutations and individual competition, i.e., classical natural selection. Accordingly, symbiogenic theory suggests that endosymbiosis may be a powerful force in generating evolutionary novelty, beyond that which can be explained by natural selection alone.<ref>{{Cite journal |last=O'Malley |first=Maureen A. |date=2015-08-18 |title=Endosymbiosis and its implications for evolutionary theory |journal=Proceedings of the National Academy of Sciences |volume=112 |issue=33 |pages=10270–10277 |doi=10.1073/pnas.1421389112 |doi-access=free |pmc=4547300 |pmid=25883268}}</ref>