Editing Symbiogenesis (section)

== Evidence ==

There are many lines of evidence that mitochondria and plastids including chloroplasts arose from bacteria.<ref name="Kimball">Kimball, J. 2010. [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Endosymbiosis.html  ''Kimball's Biology Pages''.] {{Webarchive|url=https://web.archive.org/web/20170622083131/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Endosymbiosis.html|date=2017-06-22}} Accessed October 13, 2010. An online open source biology text by Harvard professor, and author of a general biology text, John W. Kimball.</ref><ref name="Reece">Reece, J., Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson, 2010. ''Campbell Biology.'' 9th Edition Benjamin Cummings; 9th Ed. (October 7, 2010)</ref><ref name="Raven">{{cite book |last1=Raven |first1=P. |first2=George |last2=Johnson |first3=Kenneth |last3=Mason |first4=Jonathan |last4=Losos |first5=Susan |last5=Singer |display-authors=3 |title=Biology |publisher=McGraw-Hill |edition=9th |date=January 14, 2010 }}</ref><ref name="Gray1992">{{cite book |last1=Gray |first1=M. W. |year=1992 |title=The Endosymbiont Hypothesis Revisited |series=International Review of Cytology |volume=141 |pages=233–357 |doi=10.1016/S0074-7696(08)62068-9 |pmid=1452433 |isbn=9780123645449 }}</ref><ref name="Zimorski2014">{{cite journal |last1=Zimorski |first1=V. |last2=Ku |first2=C. |last3=Martin |first3=W. F. |last4=Gould |first4=S. B. |title=Endosymbiotic theory for organelle origins |journal=Current Opinion in Microbiology |volume=22 |pages=38–48 |date=December 2014 |pmid=25306530 |doi=10.1016/j.mib.2014.09.008 }}</ref>

* New mitochondria and plastids are formed only through [[binary fission]], the form of cell division used by bacteria and archaea.<ref name="Margolin2005">{{cite journal |last=Margolin |first=William |title=FtsZ and the division of prokaryotic cells and organelles |journal=Nature Reviews. Molecular Cell Biology |volume=6 |issue=11 |pages=862–71 |date=November 2005 |pmid=16227976 |pmc=4757588 |doi=10.1038/nrm1745 }}</ref>
* If a cell's mitochondria or chloroplasts are removed, the cell does not have the means to create new ones.<ref>{{cite book |last1=Wise |first1=Robert R. |last2=Hoober |first2=J. Kenneth |title=Structure and function of plastids |year=2007 |publisher=Springer |location=Berlin |isbn=9781402065705 |page=104 |url=https://books.google.com/books?id=FKeCVPbJ3asC&pg=PA104 }}</ref> In some [[algae]], such as ''[[Euglena]]'', the plastids can be destroyed by certain chemicals or prolonged absence of light without otherwise affecting the cell: the plastids do not regenerate.
* [[Transport proteins]] called [[porin (protein)|porins]] are found in the outer membranes of mitochondria and chloroplasts and are also found in bacterial cell membranes.<ref>{{cite journal |last1=Fischer |first1=K. |last2=Weber |first2=A. |last3=Brink |first3=S. |last4=Arbinger |first4=B. |last5=Schünemann |first5=D. |last6=Borchert |first6=S. |last7=Heldt |first7=H. W. |last8=Popp |first8=B. |last9=Benz |first9=R. |last10=Link |first10=T. A. |display-authors=3 |title=Porins from plants. Molecular cloning and functional characterization of two new members of the porin family |journal=The Journal of Biological Chemistry |volume=269 |issue=41 |pages=25754–60 |date=October 1994 |doi=10.1016/S0021-9258(18)47312-7 |pmid=7523392 |doi-access=free }}</ref><ref>{{cite journal |last1=Zeth |first1=K. |last2=Thein |first2=M. |title=Porins in prokaryotes and eukaryotes: common themes and variations |journal=The Biochemical Journal |volume=431 |issue=1 |pages=13–22 |date=October 2010 |pmid=20836765 |doi=10.1042/BJ20100371 |s2cid=22073622 }}</ref><ref>{{cite journal |last1=Fairman |first1=J. W. |last2=Noinaj |first2=N. |last3=Buchanan |first3=S. K. |title=The structural biology of β-barrel membrane proteins: a summary of recent reports |journal=Current Opinion in Structural Biology |volume=21 |issue=4 |pages=523–331 |date=August 2011 |pmid=21719274 |pmc=3164749 |doi=10.1016/j.sbi.2011.05.005 }}</ref>
* A [[membrane lipid]] [[cardiolipin]] is exclusively found in the inner mitochondrial membrane and bacterial cell membranes.<ref>{{cite journal |last1=Mileykovskaya |first1=E. |last2=Dowhan |first2=W. |title=Cardiolipin membrane domains in prokaryotes and eukaryotes |journal=Biochimica et Biophysica Acta (BBA) - Biomembranes |volume=1788 |issue=10 |pages=2084–91 |date=October 2009 |pmid=19371718 |pmc=2757463 |doi=10.1016/j.bbamem.2009.04.003 }}</ref>
* Some mitochondria and some plastids contain single circular DNA molecules that are similar to the DNA of [[bacteria]] both in size and structure.<ref name="Timmis">{{cite journal |last1=Timmis |first1=Jeremy |last2=Ayliffe |first2=Michael |last3=Huang |first3=Chun |last4=Martin |first4=William |title=Endosymbiotic gene transfer: organelle genomes forge eukaryotic chromosomes |journal=Nature Reviews. Genetics |volume=5 |issue=2 |pages=123–35 |date=February 2004 |pmid=14735123 |doi=10.1038/nrg1271 |s2cid=2385111 }}</ref>
* [[Comparative genomics|Genome comparisons]] suggest a close relationship between mitochondria and [[Alphaproteobacteria]].<ref>{{cite journal |last1=Munoz-Gomez |first1=Sergio |last2=Susko |first2=Edward |last3=Williamson |first3=Kelsey |last4=eme |first4=Laura |last5=Slamovits |first5=Claudio H. |last6=Moreira |first6=David |last7=López-García |first7=Purificación |last8=Roger |first8=Andrew J. |display-authors=3 |title=Site-and-branch-heterogeneous analyses of an expanded dataset favour mitochondria as sister to known Alphaproteobacteria |journal=Nature Ecology and Evolution |volume=6 |pages=253–62 |date=January 2022 |issue=3 |doi=10.1038/s41559-021-01638-2 |pmid=35027725 |bibcode=2022NatEE...6..253M |s2cid=245958471 }}</ref>
* Genome comparisons suggest a close relationship between plastids and [[cyanobacteria]].<ref>{{cite journal |last1=Dagan |first1=Tal |last2=Roettger |first2=Mayo |last3=Stucken |first3=Karina |last4=Landan |first4=Giddy |last5=Koch |first5=Robin |last6=Major |first6=Peter |last7=Gould |first7=Sven B. |last8=Goremykin |first8=Vadim V. |last9=Rippka |first9=Rosmarie |last10=Tandeau de Marsac |first10=Nicole |last11=Gugger |first11=Muriel |last12=Lockhart |first12=Peter J. |last13=Allen |first13=John F. |last14=Brune |first14=Iris |last15=Maus |first15=Irena |last16=Pühler |first16=Alfred |last17=Martin |first17=William F. |display-authors=3 |title=Genomes of Stigonematalean cyanobacteria (subsection V) and the evolution of oxygenic photosynthesis from prokaryotes to plastids |journal=Genome Biology and Evolution |volume=5 |issue=1 |pages=31–44 |year=2013 |pmid=23221676 |pmc=3595030 |doi=10.1093/gbe/evs117 }}</ref>
* Many genes in the genomes of mitochondria and chloroplasts have been lost or transferred to the nucleus of the host cell. Consequently, the chromosomes of many eukaryotes contain genes that originated from the genomes of mitochondria and plastids.<ref name="Timmis"/>
* Mitochondria and plastids contain their own [[ribosome]]s; these are more similar to those of bacteria (70S) than those of eukaryotes.<ref name="Manuell">{{cite journal |last1=Manuell |first1=Andrea L. |last2=Quispe |first2=Joel |last3=Mayfield |first3=Stephen P. |title=Structure of the chloroplast ribosome: novel domains for translation regulation |journal=PLOS Biology |volume=5 |issue=8 |pages=e209 |date=August 2007 |pmid=17683199 |pmc=1939882 |doi=10.1371/journal.pbio.0050209 |doi-access=free }}</ref>
* Proteins created by mitochondria and chloroplasts use [[N-formylmethionine]] as the initiating amino acid, as do proteins created by bacteria but not proteins created by eukaryotic nuclear genes or archaea.<ref name="Schwartz">{{cite journal |last1=Schwartz |first1=James H. |last2=Meyer |first2=Ralph |last3=Eisenstadt |first3=Jerome M. |last4=Brawerman |first4=George |title=Involvement of N-formylmethionine in initiation of protein synthesis in cell-free extracts of Euglena gracilis |journal=Journal of Molecular Biology |volume=25 |issue=3 |pages=571–4 |date=May 1967 |pmid=5340700 |doi=10.1016/0022-2836(67)90210-0 }}</ref><ref name="Smith">{{cite journal |last1=Smith |first1=A.E. |last2=Marcker |first2=K.A. |title=N-formylmethionyl transfer RNA in mitochondria from yeast and rat liver |journal=Journal of Molecular Biology |volume=38 |issue=2 |pages=241–3 |date=December 1968 |pmid=5760639 |doi=10.1016/0022-2836(68)90409-9 }}</ref>

{{plain image with caption|Chloroplast-cyanobacterium comparison.svg|Comparison of [[chloroplast]]s and [[cyanobacteria]] showing their similarities. Both chloroplasts and cyanobacteria have a double membrane, [[DNA]], [[ribosome]]s, and [[chlorophyll]]-containing [[thylakoid]]s.|650px|center|bottom|triangle|#3fad47}}