Posted on 09/08/2004 4:50:10 PM PDT by PatrickHenry
According to a new report, complex cells like those in the human body probably resulted from the fusion of genomes from an ancient bacterium and a simpler microbe, Archaea, best known for its ability to withstand extreme temperatures and hostile environments. The finding provides strong evidence that complex cells arose from combinations of simpler organisms in a symbiotic effort to survive.
Jim Lake and Maria Rivera, at the University of California-Los Angeles (UCLA), report their finding in the Sept. 9 issue of the journal Nature.
Scientists refer to both bacteria and Archaea as "prokaryotes" -- a cell type that has no distinct nucleus to contain the genetic material, DNA, and few other specialized components. More-complex cells, known as "eukaryotes," contain a well-defined nucleus as well as compartmentalized "organelles" that carry out metabolism and transport molecules throughout the cell. Yeast cells are some of the most-primitive eukaryotes, whereas the highly specialized cells of human beings and other mammals are among the most complex.
"A major unsolved question in biology has been where eukaryotes came from, where we came from," Lake said. "The answer is that we have two parents, and we now know who those parents were."
Further, he added, the results provide a new picture of evolutionary pathways. "At least 2 billion years ago, ancestors of these two diverse prokaryotic groups fused their genomes to form the first eukaryote, and in the processes two different branches of the tree of life were fused to form the ring of life," Lake said.
The work is part of an effort supported by the National Science Foundationthe federal agency that supports research and education across all disciplines of science and engineeringto re-examine historical schemes for classifying Earth's living creatures, a process that was once based on easily observable traits. Microbes, plants or animals were said to be related if they shared certain, mostly physical, characteristics. DNA technology now allows much closer scrutiny of hereditary molecules, which provides a more accurate and detailed picture of the genetic relationships between and among living things.
"New computational tools and comparative analyses will undoubtedly find instances in which the evolutionary record will need to be set straight," said James Rodman, a program officer in NSF directorate for biology, which funded the research. "This new fellowship among microbiologists, evolutionists, and computationalists will provide a much fuller picture of the relatedness of living things."
Lake and Rivera analyzed and compared the genomes of 30 microorganisms selected from the three categories (eukaryotes, bacteria and Archaea). All of the microbes contained about the same number of genes. The researchers then used the computer to produce genome combinations that reflected the most likely ancestors of modern eukaryotes. Their analysis, they say, showed that two ancient prokaryotes - one most similar to a bacterium, and one an Archaea - combined genomes out of a mutually advantageous need to survive.
That theory, known as endosymbiosis, has been a popular explanation of how eukaryotic cells acquired smaller components to carry out cellular processes. According to the report, modern eukaryotes obtained genes required to operate the cell from the bacterial side of the family, and the information-carrying genes from the Archaea side.
Further, the authors say, the work also sheds light on the horizontal transfer of genessideways from organism to organism, rather than from parent to offspring. The U.S Department of Energy, the National Institutes of Health, and NASA also supported this work.
troll-bait placemarker
This has been the big deal in evolution, how we stayed monocellular for 4 billion years and then "Ta da" muticellular real quick
"how we stayed monocellular for 4 billion years and then "Ta da" muticellular real quick"
Explain, please.
More evidence for endosymbiosis. Not surprising, as it already made a lot of sense.
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A scientific journal has published a paper that argues in favour of intelligent design the first time such material has appeared in a peer-reviewed publication, according to biologists who track the issue. The paper appeared in a low-impact journal, Proceedings of the Biological Society of Washington. But critics say that it could still be used by advocates of intelligent design to get the subject on to US school curricula (see Nature 416, 250; 2002).
The article comes from the Discovery Institute in Seattle, Washington, a leading promoter of the theory. In the article, senior fellow Stephen Meyer uses information theory and other techniques to argue that the complexity of living organisms cannot be explained by darwinian evolution (S. C. Meyer Proc. Biol. Soc. Wash. 117, 213239; 2004).
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I thought people who participate in these threads would appreciate that bit on info.
As far as the Ring of Life study, as usual it won't be discussed in any coherent manner here.
take look at the record... the Cambrian explosion was a multicellular explosion
Always learning new stuff.
IOW, theory didn't hold up.
Don't be scared.
If anything I did ever earned criticism like that I'd have to enter the witness protection program.
In my mind he has a definite flaw in his reasoning. The early bacteria evolved (or were created) in METHANE atmosphere on Earth. Later after plants arose with photosynthesis, oxygen appeared in the atmosphere. The author wants us to believe that one or two methane utilizing bacteria combined to produce a eukaryotic cell that is oxygen based. I don't think so.
In the interest of proper scientific nomenclature, should these be referred to as:
glowing green fatty prokaryote bubbles (GGFPB)
bubbly glowing green prokaryotic fatties (BGGPF)
fat bubbling prokaryotes glowing green (FBPGG)
green Archaea genome microbus-extremus (GAGME)
ring of fused life (ROFL)
Other:
This research does not address nonocellular vs multicelular.
Your understanding of this research is utterly incomplete.
What are the criticisms of the paper? (or perhaps, first, what is the paper about?).
I thought these guys were rather gentle in their review.
Mitochondria.
Aye, there's the rub. To argue that something "cannot be explained" by blah, blah, blah. This is a purely subjective judgment, (substitute 'opinion.')
The criticism referenced by VR in post #10 goes into some detail on this point but how many times do we have to revisit the same invalid arguments?
One cannot "Prove a Negative" (i.e., "cannot be explained") and even if one could - that wouldn't prove a "Designer" since another explanation not yet considered may be the actual answer.
Therefore, proving evolution wrong does not prove anything other than evolution is wrong. This has not been done and cannot be done. Evolution can be abandoned for lack of evidence, but not 'proven' wrong.
Proving the existence of a "Designer" apriori to the experience of the "designed," which is the prerequisite of proof that life is "designed" is logically impossible.
Thus the question shifts from - is there any evidence for the theory of evolution - to - is there any evidence for anything else? And this, so far, is what has never been done.
Too lazy to follow the links?
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