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RNA Getting Lengthy

ScienceDaily reports on an interesting experiment relevant to OOL scenarios.

With the aid of a straightforward experiment, researchers have provided some clues to one of biology’s most complex questions: how ancient organic molecules came together to form the basis of life.

Specifically, this study demonstrated how ancient RNA joined together to reach a biologically relevant length.

RNA, the single-stranded precursor to DNA, normally expands one nucleic base at a time, growing sequentially like a linked chain. The problem is that in the primordial world RNA molecules didn’t have enzymes to catalyze this reaction, and while RNA growth can proceed naturally, the rate would be so slow the RNA could never get more than a few pieces long (for as nucleic bases attach to one end, they can also drop off the other).

Ernesto Di Mauro and colleagues examined if there was some mechanism to overcome this thermodynamic barrier, by incubating short RNA fragments in water of different temperatures and pH.

They found that under favorable conditions (acidic environment and temperature lower than 70 degrees Celsius), pieces ranging from 10-24 in length could naturally fuse into larger fragments, generally within 14 hours.

The RNA fragments came together as double-stranded structures then joined at the ends. The fragments did not have to be the same size, but the efficiency of the reactions was dependent on fragment size (larger is better, though efficiency drops again after reaching around 100) and the similarity of the fragment sequences.

The researchers note that this spontaneous fusing, or ligation, would a simple way for RNA to overcome initial barriers to growth and reach a biologically important size; at around 100 bases long, RNA molecules can begin to fold into functional, 3D shapes.

Journal reference:

Samanta Pino, Fabiana Ciciriello, Giovanna Costanzo and Ernesto Di Mauro. Nonenzymatic RNA ligation in water. J. Biol. Chem, DOI: 10.1074/jbc.M805333200

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14 Responses to RNA Getting Lengthy

  1. Thanks for posting this. I’m glad to see intellectual honesty wherever it appears.

  2. I don’t understand how one can make the intellectual jump from the study findings to the declarative sentence ” specifically this study demonstrated how ancient RNA joined together to reach a biologically relevent length”. I think the word ‘possibly’ or ‘perhaps’ belongs in the sentence. We don’t even know if the ‘RNA world’ ever existed. Where is the intellectual honesty?

  3. gpuccio:

    I am not going to comment in detail about this study for two good reasons:

    1) I couldn’t read the full text.

    2) It’s Christmas :-)

    I remain anyway of the idea that all of these studies about OOL (see also the chyral aminoacids thread) are really extremely artificial, and have almost no relevance to theories which are in themselves pure imagination, and I can feel some true sympathy for the poor researchers trying to validate intellectual constructions which make no sense.

    Anyway, the problem of how to elongate RNA in ansence of enzymes is just the least of the many and insourmountable problems of the RNA world scenario, as I have recently debated in other threads. Which reamins, however, the “least absurd” among materialist OOL scenarios.

    But, as I said before, it’s Christmas. Best wishes to all.

  4. I don’t know why, but it seems that I directed my last post to myself. Is that a sign of narcissism or just schizophrenia?

  5. Don’t forget Stephen C. Meyer comment on the RNA world: “[F]or a single strand of RNA to replicate, there must be an identical RNA molecule close by. To have a reasonable chance of having two identical RNA molecules of the right length would require a library of ten billion billion billion billion billion billion RNA molecules – and that effectively rules out any chance origin of a primitive replicating system.”

    On top of that, were these experiments even realistic to the earth’s primitive environment?

  6. RNA, the single-stranded precursor to DNA,

    Is there an experiment that demonstrates that RNA can become DNA?

    It seems that they are having a hard enough time to get RNA to be RNA.

    But heck they “know” the RNA world came first and therefor RNA was the precursor to DNA.

    I love how their “science” works. ANYTHING but the design inference…

  7. And don’t forget the problem, always overlooked, of how the RNA – DNA replicator would transform his informations in protein information (or just build that one anew?)

    But I feel a little stupid in commenting on RNA world and OOL theories. Is it really worthwhile? Who has ever seen an RNA based living being? Where is the empirical foundation that it may even exist? Is science really reduced to fairy tales?

    RNA beings… please, go in your labs and try to build an RNA bacterium, or whatever… or at least try a model: we need such genes, such rybozimes, such metabolism. A membrane? Made of RNA? Of clay? RNA flagella? What else?

    And let’s remember, nothing, absolutely nothing of that kind has ever been observed! Nothing! All we have is a buch of rybozimes, in the context of perfectly normal DNA and protein beings.

    The RNA world is pure imagination. It’s not better than vampyrs and unicorns, and much less likely. Compared to OOL theorists, astrophysicists are simple and practical people.

    Let’s face the truth: the only, and I insist the “only” reason for an RNA world theory is to bypass the very simple fact that a DNA and protein world could never, never have arisen by chance, for the well known chicken and egg problem, which even a child would easily understand.

    Of course, unless it was designed…

  8. gpuccio,

    “Who has ever seen an RNA based living being?”

    no one has ever proposed that the entire organism was made of RNA. RNA is proposed to have been the information storage unit, much as we see in RNA viruses today.

    “RNA beings… please, go in your labs and try to build an RNA bacterium, or whatever… or at least try a model: we need such genes, such rybozimes, such metabolism. A membrane? Made of RNA? Of clay? RNA flagella? What else?”

    one hypothesis is that phospholipids self-assembled (as they do naturally in aqueous solutions) to form micelles (simple membranes) around RNA strands, making proto-cells. this is a testable hypothesis that is actively being tested (including seeing if proto-cells can be viable). may or may not be correct, but we’ll never know until we try, right?

    “..for the well known chicken and egg problem..”

    there is no chicken and egg problem. chickens are birds. birds evolved from dinosaurs. dinosaurs laid eggs. therefore, egg before chicken. QED :)

  9. Merry Christmas ALL:

    This following music video is very strange in that I just stuck the song I happened to find to a clip I just happened to find, but look at How well they go together guys,,,Its as if the music and the clip I were “Intelligently Designed” for each other by you know Who.

    Christ Is Come – Jeremy Camp – Nativity Movie Scene

    http://www.godtube.com/view_vi.....d216ac5483

  10. The geologic evidence shows that no prebiotic soup ever existed and furthermore that “complex photosynthetic life” appeared abruptly on earth in the oldest sedimentary rocks ever found on Earth:

    Is the Chemical Origin of Life (Abiogenesis) a Realistic Scenario?

    http://www.godandscience.org/e.....mlife.html

    excerpt:

    Comparison of the dates of meteor impacts on the moon, Mercury, and Mars indicate that at least 30 catastrophic meteor impacts must have occurred on the earth from 3.8 to 3.5 billion years ago (15). These impacts were of such large size that the energy released would have vaporized the entirety of the earth’s oceans (16), destroying all life.

    Complex bacterial life (oxygenic photosynthesis) had appeared by 3.7 billion years ago (17), leaving virtually no time for prebiotics to have evolved into the first life forms.

    as well this following site has a more detailed critique on the molecular level

    An Evolutionist criticisms of the RNA World conjecture:

    http://www.answersingenesis.or.....th_RNA.asp

  11. 11

    Joseph…RNA can become DNA via reverse transcriptase. But then, where did reverse transcriptase come from? And the free floating nucleotides? And how does the uracil in RNA become thymine?

  12. There are a few problems with the RNA world theory, notably, that it fails to explain where the energy came from to fuel the production of the first RNA molecules. It also fails to explain where RNA came from in the first place.

  13. WeaselSpotting-

    Good point however with reverse transcriptase, both RNA and DNA already exist.

    I am looking for how RNA can become DNA when DNA does not yet exist.

    Reverse transcriptase is nice when there is something to revert to. But in the case of a RNA world RNA can only revert to nucleotides/ sides. And that isn’t going to help the other side at all.

  14. On The Origin Of Life And God – Henry F. Schaefer, III PhD.

    http://www.godtube.com/view_vi.....43dd87e4e8

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