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Topic: Last universal ancestor


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In the News (Mon 21 Dec 09)

  
  Last universal ancestor - Biocrawler   (Site not responding. Last check: 2007-10-16)
Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend.
The last universal ancestor already had all of the properties that are shared by all currently living organisms, such as a (prokaryotic) cell structure, DNA, the modern genetic code and mRNA, tRNA and ribosome mediated transcription.
All its contemporaries have since become extinct, however; only LUA's genetic heritage lives on to this day.
www.biocrawler.com /encyclopedia/Last_universal_ancestor   (156 words)

  
  Last universal ancestor - Wikipedia, the free encyclopedia   (Site not responding. Last check: 2007-10-16)
Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend.
As such, it is the most recent common ancestor of the set of all currently living organisms.
Combining the simple coalescence model of cladogenesis with rare HGT [horizontal gene transfer] events suggest there was no single last common ancestor that contained all of the genes ancestral to those shared among the three domains of life.
en.wikipedia.org /wiki/Last_universal_ancestor   (733 words)

  
 Common descent - Wikipedia, the free encyclopedia
In biology, the theory of universal common descent proposes that all organisms on Earth are descended from a common ancestor or ancestral gene pool.
This theory is now generally accepted by biologists, and the last universal common ancestor (LUCA or LUA), that is, the most recent common ancestor of all currently living organisms, is believed to have appeared about 3.5 billion years ago (see: origin of life).
The universality of the genetic code is generally regarded by biologists as definitive evidence in favor of the theory of universal common descent (UCD) for all bacteria, archaea, and eukaryotes (see Three domain system).
en.wikipedia.org /wiki/Common_descent   (978 words)

  
 Common ancestor - EvoWiki
Identifying common ancestors is one of the tasks you have to do when systematically ordering known species.
Usually it is these recent common ancestors that biologists/paleontologists are concerned with, and the most recent link between later species would be the last common ancestor (LCA) while the LCA of all contemporary life on Earth is known as the Last Universal Common Ancestor (LUCA).
A fossil of the common ancestor or a related form is a transitional fossil.
wiki.cotch.net /index.php/Common_ancestor   (281 words)

  
 My Name is LUCA -- The Last Universal Common Ancestor by Anthony M. Poole, Ph.D.
LUCA is short for Last Universal Common Ancestor, and it is from this 'organism' that every living cell on the planet has descended.
Nevertheless, universal features are important because they describe a 'lower limit' from which to build upon, and importantly, all these attempts converge on agreement insofar as concluding that LUCA was quite complex.
Universal protein families and the functional content of the last universal common ancestor.
www.actionbioscience.org /newfrontiers/poolepaper.html   (7113 words)

  
 The world's top common descent websites
In biology, the theory of universal common descent proposes that all organisms on Earth are descended from a common ancestor or ancestral gene pool.¹
This theory is now generally accepted by biologists, and the last universal common ancestor (LUCA), that is, the most recent common ancestor of all organisms, is believed to have appeared about 3.5 billion years ago (see: origin of life).
Some creationists do not accept the theory of universal common descent, arguing that humanity was created by God in a distinct act of creation, whereas the rest of life evolved.
www.websbiggest.com /wiki-article-tab.cfm/common_descent   (924 words)

  
 Mitochondrial Eve - Wikipedia, the free encyclopedia
Mitochondrial Eve is the name given by researchers to the woman who is the most recent common matrilineal ancestor of all living humans.
However, at times in the past, as certain lineages died out, the status of common matrilineal ancestor would have been passed to a descendant of the previous matrilineal ancestor.
Mitochondrial Eve is sometimes referred to as African Eve, an ancestor who has been hypothesized on the grounds of fossil as well as DNA evidence.
en.wikipedia.org /wiki/Mitochondrial_Eve   (1453 words)

  
 universal ancestor and the rise of life -- universal ancestor and the rise of life   (Site not responding. Last check: 2007-10-16)
Jabotinsky, the ideological ancestor of Likud and the Neocons...
last universal common ancestor of all organisms is...
Beginning with a single universal ancestor, the magnificent diversity of life has come about through a series of branchings of new species, which eventually gave rise to the major branches of the...
www.universallifeyoga.com /universalancestorandtheriseoflife   (3251 words)

  
 Last universal ancestor: Facts and details from Encyclopedia Topic   (Site not responding. Last check: 2007-10-16)
Last universal ancestor (LUA), EHandler: no quick summary.
The last universal ancestor already had all of the properties that are shared by all currently living organisms, EHandler: no quick summary.
Transcription is the process through which a dna sequence is enzymatically copied by an rna polymerase to produce a complementary rna....
www.absoluteastronomy.com /encyclopedia/l/la/last_universal_ancestor.htm   (441 words)

  
 Nat' Academies Press, Tempo and Mode in Evolution: Genetics and Paleontology 50 Years After Simpson (1995)
Distinct properties of rRNAs suggested that the ribosome of the last common ancestor was a primitive ribosome and that the last common ancestral cell was a primitive "progenote," still experiencing progressive Darwinian evolution.
Rooting the Universal Tree Woese felt that the differences between archaebacteria and either eubacteria or eukaryotes were of a sufficiently fundamental nature to indicate that all three primary kingdoms must have begun to diverge during the period of progressive evolution from a progenote.
The last common archaebacterial/eubacterial ancestral genome must have had operons just like this and likely was very much like the present E. coli or Haloferax genomes in other specific and general respects (including origins and mechanism of replication, and so forth).
www.nap.edu /books/0309051916/html/3.html   (6934 words)

  
 EMBL - About Us - News and Communication - Press Releases - 1 July 2005 - Trees, vines and nets: microbial evolution ...   (Site not responding. Last check: 2007-10-16)
Since the time of Darwin, the evolutionary relationships between organisms have been represented as a tree, with the common ancestors at the base of the trunk and the most recently evolved species at the tips of the branches.
Victor Kunin, previously a PhD student in Christos Ouzounis's group, and their colleagues have now constructed a map of microbial evolution, going back billions of years to the last universal common ancestor, that includes these horizontal lines.
The last universal common ancestor is shown as a yellow sphere.
www.embl.org /aboutus/news/press/2005/press1jul05.html   (733 words)

  
 Nigel Goldenfeld's Group: Dynamics and Pattern Formation
Empirically, it is found that the number of species S in a biome of area A scales with a power law of A. Typically, this power law is found to be in the range 0.2-0.25 although other values are sometimes found, depending on the nature of the habitat.
The universal nature of the species-area law suggests that there is a general mechanism for its occurrence.
Evolution of the genetic code: Over the last decade, it has become clear that the canonical genetic code is not a "frozen accident", but has been highly optimized with respect to a property of amino acids known as the "polar requirement", first measured by Carl Woese.
guava.physics.uiuc.edu /projects/quant_bio_overview.html   (649 words)

  
 Astrobiology Magazine ::
The last common ancestor of all organisms living today.
Lateral gene transfer may have been widespread in the early stages of life on Earth and this complicates the interpretation of the tree of life.
Another term used for the Last Common Ancestor of all living organisms.
www.astrobio.net /news/index.php?module=Semantics&func=display&cid=1<r=L   (265 words)

  
 No. 2025: L.U.C.A.
The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.
We've determined that humans, horses, and cats, have diverged more than rodents have, from the common ancestor of us all.
I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.
www.uh.edu /engines/epi2025.htm   (536 words)

  
 BioMed Central | Full text | Algorithms for computing parsimonious evolutionary scenarios for genome evolution, the ...
Thus, comparative genomics might potentially undermine the very idea of a universal species tree because, inasmuch as HGT is shown to make a substantial contribution to genome evolution, no tree can, in principle, fully reflect the course of evolution of species [7,9,11,18,19].
We further concentrate on the reconstruction of the gene repertoire of the hypothetical Last Universal Common Ancestor (LUCA) of all extant life forms and examine the biological features of the LUCA gene sets reconstructed with different algorithm parameters.
The topology of the species tree in Figure 5 was derived from the concatenated tree of universal ribosomal proteins [24] and is close to the apparent consensus of various genome-tree approaches [30].
www.biomedcentral.com /1471-2148/3/2   (11203 words)

  
 Biology Direct | Full text | Did the last common ancestor have a biological membrane?
The idea of a membrane-less, minerally compartmentalised universal ancestor has been proposed because archaebacteria and eubacteria have membrane lipids of different chemical composition and chirality (archaebacteria have isoprenoid ethers of glycerol-1-phosphate, eubacteria have fatty acid esthers of glycerol-3-phosphate) and because these different lipids are synthesized by mostly non-homologous enzymes [1,2,8].
Those authors who advocate a cellularised universal ancestor argue that eu- and archaebacterial membranes either evolved from heterochiral membranes [1], or by lipid phase segregation [9], or by the replacement of eubacterial lipids by archaebacterial ones due to adaptation to hyperthermophily [8].
The universality of this arrangement indicates that the hydrophobic layers of the universal ancestor into which SecY was integrated had a hydrophobic core and two hydrophilic sides.
www.biology-direct.com /content/1/1/35   (2309 words)

  
 Cafe Arcane - Scientists zero in on suspected common ancestor of all living things -- A cozy, caffeinated corner of the ...
They call it LUCA - shorthand for the "last universal common ancestor" - and they think it inhabited the Earth 3 billion to 4 billion years ago.
The quest for a universal common ancestor is made possible by the fact that all organisms from LUCA on down share a few hundred or thousand basic genes that enable them to eat, grow and reproduce.
Those universally inherited genes provide the clues that evolutionary scientists are using to figure out what LUCA must have been like.
www.arcane.org /modules.php?name=News&file=article&sid=774   (725 words)

  
 FOCUS - February 11, 2005 - GENOMICS: Gain and Loss of Amino Acids Detected Across All of Life
But, as their computers sort through the contemporary data sets, the researchers hear the echo of the original genome of the last universal common ancestor clicking into place more than 3.5 billion years ago.
“The most plausible hypothesis is that we are observing a universal, intrinsic trend that emerged before the last common ancestor of all extant organisms,”; says a team led by Shamil Sunyaev, HMS assistant professor of medicine and health sciences and technology at Brigham and Women’s Hospital.
In the last 10 million years, four of the oldest amino acids have been dropping out of proteins ranging from yeast to mammals, while five amino acids have been hopping on.
focus.hms.harvard.edu /2005/Feb11_2005/genomics.html   (1166 words)

  
 The ID Report - Thinkquote of the day 1: Key origin of life researcher doubts that there was a single common ancestor
I presume Woese means the *last* universal ancestor" (LUCA) of all organisms *alive today*, not the *first* common ancestor, i.e.
the last universal common ancestor of all *living* organisms, which is a tiny subset of all organisms that have *ever* lived.
That there is a difference between *last* common ancestor and *first* common ancestor is evident in humans when the *last* common ancestor of all humans *alive today* is estimated to have lived only in 1,415BC [http://tinyurl.com/efh23], and yet modern humans have been in Australia since at least 40,000 years ago [http://tinyurl.com/jvoer ].
www.arn.org /blogs/index.php/2/2006/08/21/lstrongglemgthinkquote_of_the_day_1_l_em   (769 words)

  
 Last Universal Common Ancestor - EvoWiki
The Last Universal Common Ancestor (LUCA), is a hypothetical organism supposed to be the most recent common ancestor of all living organisms on Earth.
It is also believed that multiple endosymbiotic events would distort the cladistic representation of such an organism if it were to ever have existed.
This page was last modified 20:34, 4 April 2007.
wiki.cotch.net /index.php/Last_Universal_Common_Ancestor   (84 words)

  
 Penny
We also raise the possibility that the last common ancestor of plants and animals contained some type of exon definition and that this mechanism was replaced in some genes and lineages by intron definition, possibly as a result of intron loss and/or intron shortening.
Although the last common ancestor of extant eukaryotes appears to show much of the molecular complexity seen today, we do not, from this work, infer anything of the properties of the earlier ‘‘first eukaryote.’’;.
The last universal common ancestor may have been mesophilic and could have had many features of the eukaryote genome, but its cytology is unknown.
awcmee.massey.ac.nz /people/dpenny/abstract_RNA.htm   (3084 words)

  
 The Panda's Thumb: August 2005
In a post earlier today, I noted that a group of creationists are suing the University of California system in order to force UC to accept several of their classes that are currently not considered adequate.
Intelligent Design adds nothing to the scientific, investigative curiosity about the nature of our universe, and as such is a waste of time, energy and resources much better spent in providing our children with the tools necessary to succeed in a multi-cultural and multi-religious society.
Last year Ian, Steve, and I wrote a critique of a flawed anti-“Darwinian processes” paper by Michael Behe and David Snoke.
www.pandasthumb.org /archives/2005/08   (7237 words)

  
 Honolulu Star-Bulletin Hawaii News
University of Hawaii researchers have made a breakthrough that could lead to the creation of substitutes for blood, according to UH microbiology professor Maqsudul Alam.
"The contemporary viewpoint is (the last universal common ancestor) had these proteins already, and they could function in using oxygen to generate energy that maybe required a little bit of oxygen," Freitas said.
Alam said "intriguing connections" might exist between the "last universal common ancestor" and the evolution of mechanisms that sense oxygen, carbon monoxide, nitric oxide and hydrogen sulfide.
starbulletin.com /2004/04/20/news/story11.html   (434 words)

  
 Wikinfo | Evolution   (Site not responding. Last check: 2007-10-16)
Most biologists believe that all life on Earth is descended from one common ancestor, affectionately called LUCA (Last Universal Common Ancestor).
The current dominant theory of evolution is known as "the modern synthesis", referring to the synthesis of Darwin's theory of evolution by natural selection and Mendel's theory of the gene.
Further evidence of the universal ancestry of life is that abiogenesis has never been observed under controlled conditions, indicating that the origin of life from non-life, is either very rare or only happens under conditions that are not at all like those of modern earth.
www.wikinfo.org /wiki.php?title=Evolution   (3451 words)

  
 The Search for LUCA - Last Universal Common Ancestor Natural History - Find Articles
We infer the existence of this Last Universal Common Ancestor--or LUCA--from the many features shared by all organisms, most notably the unique code that translates the language of DNA into the language of proteins, the things that actually do all the work inside cells.
This undoubtedly tiny organism was the last common ancestor of all present-day eukaryotes (organisms possessing cells with a nucleus).
The only explanation for these contradictory patterns, according to W. Ford Doolittle, of Dalhousie University in Nova Scotia, is to assume that at some point in the early history of life, there was promiscuous sharing of genes among species--or even mergers of whole organisms.
www.findarticles.com /p/articles/mi_m1134/is_9_109/ai_67410993   (738 words)

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