Editing Carl Woese (section)

=== Evolution of primary cell types ===
Woese also speculated about an era of rapid evolution in which considerable [[horizontal gene transfer]] occurred between organisms.<ref name="pace2011pnas">{{Cite journal
| title = Phylogeny and beyond: Scientific, historical, and conceptual significance of the first tree of life
| doi = 10.1073/pnas.1109716109
| issn = 1091-6490 
| volume = 109
| issue = 4
| pages = 1011–1018
| last1 = Pace
| first1 = Norman R.
| author-link1 = Norman R. Pace
| first2 = Jan 
| last2 = Sapp
| author-link2 = Jan Sapp
| first3 = Nigel
| last3 = Goldenfeld
| journal = Proceedings of the National Academy of Sciences
| date = 2012-01-24
|bibcode = 2012PNAS..109.1011P
| pmid=22308526
| pmc=3268332| doi-access = free
}}</ref><ref name="woese2002cells">{{Cite journal
| title = On the evolution of cells
| doi = 10.1073/pnas.132266999
| volume = 99
| issue = 13
| pages = 8742–8747
| last = Woese
| first = Carl R.
| journal = Proceedings of the National Academy of Sciences of the United States of America
| date = 2002-06-25
| pmid = 12077305
| pmc = 124369
| bibcode = 2002PNAS...99.8742W
| doi-access = free
}}</ref> First described by Woese and Fox in a 1977 paper and explored further with microbiologist [[Jane Gibson]] in a 1980 paper, these organisms, or ''[[Progenote|progenotes]]'', were imagined as protocells with very low complexity due to their error-prone translation apparatus ("noisy genetic transmission channel"), which produced high mutation rates that limited the specificity of cellular interaction and the size of the genome.<ref>{{Cite journal 
| last1 = Woese | first1 = C. R. 
| last2 = Fox | first2 = G. E. 
| title = The concept of cellular evolution 
| journal = Journal of Molecular Evolution 
| volume = 10 
| issue = 1 
| pages = 1–6 
| year = 1977 
| pmid = 903983
 | doi=10.1007/bf01796132
| bibcode = 1977JMolE..10....1W| s2cid = 24613906 
}}</ref><ref>{{Cite journal|last1=Woese|first1=Carl R.|last2=Gibson|first2=Jane|last3=Fox|first3=George E.|date=January 1980|title=Do genealogical patterns in purple photosynthetic bacteria reflect interspecific gene transfer?|url=https://www.nature.com/articles/283212a0|journal=Nature|language=en|volume=283|issue=5743|pages=212–214|doi=10.1038/283212a0|pmid=6243180|bibcode=1980Natur.283..212W|s2cid=4243875|issn=1476-4687}}</ref> This early translation apparatus would have produced a group of structurally similar, functionally equivalent proteins, rather than a single protein.<ref name="pace2011pnas"/> Furthermore, because of this reduced specificity, all cellular components were susceptible to horizontal gene transfer, and rapid evolution occurred at the level of the ecosystem.<ref name="woese2002cells"/><ref name="buchanan2010">{{Cite news|title=Evolution, but not as we know it|last=Buchanan|first=Mark|date=2010-01-23|work=New Scientist|issue=2744|volume=205|pages=34–37|issn=0262-4079}}</ref>

The transition to modern cells (the "[[Darwinian threshold|Darwinian Threshold]]") occurred when organisms evolved translation mechanisms with modern levels of fidelity: improved performance allowed cellular organization to reach a level of complexity and connectedness that made genes from other organisms much less able to displace an individual's own genes.<ref name="woese2002cells"/>

In later years, Woese's work concentrated on genomic analysis to elucidate the significance of horizontal gene transfer (HGT) for evolution.<ref name="woese2005hgt">{{Cite book
| title = Microbial Phylogeny and Evolution:Concepts and Controversies: Concepts and Controversies
| chapter = Evolving biological organization
| publisher = Oxford University Press
| pages = 99–117
|editor1= Jan Sapp
| last = Woese
| first = Carl R.
| author-link = Carl Woese
| access-date = 2013-01-04
| year = 2005
| isbn = 9780198037774
| chapter-url = https://books.google.com/books?id=SMvLpiK-fgsC&q=Evolving+Biological+Organization&pg=PA99
}}</ref> He worked on detailed analyses of the phylogenies of the aminoacyl-tRNA synthetases and on the effect of horizontal gene transfer on the distribution of those key enzymes among organisms.<ref name="woese2008">{{Cite journal 
| last1 = Woese | first1 = C. R. 
| author-link1 = Carl Woese
| last2 = Olsen | first2 = G. J. 
| last3 = Ibba | first3 = M. 
| last4 = Söll | first4 = D. 
| title = Aminoacyl-tRNA synthetases, the genetic code, and the evolutionary process 
| journal = Microbiology and Molecular Biology Reviews 
| volume = 64 
| issue = 1 
| pages = 202–236 
| year = 2000 
| pmid = 10704480 
| pmc = 98992
| doi = 10.1128/MMBR.64.1.202-236.2000
}}</ref> The goal of the research was to explain how the primary cell types (the archaeal, eubacterial, and eukaryotic) evolved from an ancestral state in the [[RNA world]].<ref name=mcb />