title: Evidence for an early prokaryotic endosymbiosis.
abstract: Endosymbioses have dramatically altered eukaryotic life, but are thought to have negligibly affected prokaryotic evolution. Here, by analysing the flows of protein families, I present evidence that the double-membrane, gram-negative prokaryotes were formed as the result of a symbiosis between an ancient actinobacterium and an ancient clostridium. The resulting taxon has been extraordinarily successful, and has profoundly altered the evolution of life by providing endosymbionts necessary for the emergence of eukaryotes and by generating Earth's oxygen atmosphere. Their double-membrane architecture and the observed genome flows into them suggest a common evolutionary mechanism for their origin: an endosymbiosis between a clostridium and actinobacterium.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of California, Los Angeles, California 90095, USA. lake@mbi.ucla.edu
authors.forename: James A
authors.initials: JA
authors.lastname: Lake
mesh_terms: D039903:Actinobacteria / Q000166:cytology*; D005075:Biological Evolution; D003013:Clostridium / Q000166:cytology*; D004705:Endocytosis; D005057:Eukaryotic Cells / Q000166:cytology; D051456:Gene Flow; D008954:Models, Biological; D010802:Phylogeny; D011387:Prokaryotic Cells / Q000145:classification / Q000166:cytology*; D013559:Symbiosis
references.citation: Nucleic Acids Res. 2004 Sep 21;32(16):4937-44
references.pmid: 15383646
references.citation: Mol Biol Evol. 2008 Jan;25(1):1-4
references.pmid: 18003601
references.citation: J Bacteriol. 2005 Sep;187(18):6258-64
references.pmid: 16159757
references.citation: Science. 1999 Jun 25;284(5423):2124-9
references.pmid: 10381871
references.citation: Science. 2002 Nov 22;298(5598):1616-20
references.pmid: 12446909
references.citation: Bioessays. 1999 Oct;21(10):880-9
references.pmid: 10497339
references.citation: Arch Microbiol. 2002 Mar;177(3):201-8
references.pmid: 11907675
references.citation: Trends Ecol Evol. 2007 Mar;22(3):114-5
references.pmid: 17239486
references.citation: Mol Biol Evol. 2006 Sep;23(9):1648-51
references.pmid: 16801395
references.citation: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3801-6
references.pmid: 10097118
references.citation: Trends Genet. 2002 Nov;18(11):577-84
references.pmid: 12414188
references.citation: Nat Rev Genet. 2008 Aug;9(8):605-18
references.pmid: 18591983
references.citation: Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):2880-1
references.pmid: 8159671
references.citation: Nature. 2001 Jul 26;412(6845):433-6
references.pmid: 11473316
references.citation: Arch Microbiol. 2000 Jul-Aug;174(1-2):50-8
references.pmid: 10985742
references.citation: Mol Biol Evol. 2008 Aug;25(8):1677-82
references.pmid: 18492661
references.citation: PLoS Genet. 2005 Nov;1(5):e65
references.pmid: 16311624
references.citation: Nature. 1998 Mar 5;392(6671):37-41
references.pmid: 9510246
references.citation: Mol Biol Evol. 2007 Aug;24(8):1761-8
references.pmid: 17513883
references.citation: Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9662-6
references.pmid: 7568193
references.citation: Nature. 2004 Mar 4;428(6978):37-43
references.pmid: 14961025
references.citation: Science. 2007 Nov 30;318(5855):1449-52
references.pmid: 17947550
references.citation: Proc Natl Acad Sci U S A. 2007 Sep 4;104(36):14260-5
references.pmid: 17726114
references.citation: Annu Rev Genet. 1999;33:351-97
references.pmid: 10690412
references.citation: Mol Biol Evol. 2003 Oct;20(10):1598-602
references.pmid: 12777514
references.citation: Nature. 2004 Sep 9;431(7005):152-5
references.pmid: 15356622
references.citation: Nature. 2008 Oct 23;455(7216):1101-4
references.pmid: 18948954
references.citation: Appl Environ Microbiol. 1989 Jul;55(7):1735-41
references.pmid: 16347966
references.citation: Nature. 2009 May 14;459(7244):180-4
references.pmid: 19444203
references.citation: Syst Biol. 2008 Dec;57(6):835-43
references.pmid: 19085327
references.citation: Science. 2007 Nov 30;318(5855):1390-1
references.pmid: 18048672
references.citation: J Bacteriol. 2008 May;190(10):3721-30
references.pmid: 18344357
references.citation: Nature. 2009 May 14;459(7244):200-6
references.pmid: 19444206
references.citation: Nature. 2009 May 14;459(7244):193-9
references.pmid: 19444205
references.citation: Biosystems. 1993;31(2-3):111-9
references.pmid: 8155843
references.citation: Mol Biol Evol. 2007 Jan;24(1):130-6
references.pmid: 17023560
references.citation: Nature. 2008 Oct 23;455(7216):1051-2
references.pmid: 18948942
references.citation: Mol Biol Evol. 2004 Apr;21(4):681-90
references.pmid: 14739244
references.citation: Theor Popul Biol. 2002 Jun;61(4):489-95
references.pmid: 12167368
references.citation: Nature. 2004 Sep 9;431(7005):134-7
references.pmid: 15356611
references.citation: Microbiol Mol Biol Rev. 1998 Dec;62(4):1435-91
references.pmid: 9841678
references.citation: Int J Syst Evol Microbiol. 2000 Sep;50 Pt 5:1829-1832
references.pmid: 11034494