1. Joined
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    28 Feb '11 15:22
    I was curious to know just how far scientists have got with abiogenesis research thinking it was such a difficulty subject that it would be very difficulty for them to get far on it but I was surprised to find just how far they have managed to go albeit with still many unanswered questions and gaps in our knowledge. I found this link:

    http://www.talkorigins.org/faqs/abioprob/originoflife.html#RNAworld

    it starts of with what I already knew:

    “...Even the simplest currently living cells contain hundreds of proteins most of which are essential to their functioning. Yet such complexity cannot have stood at the origin of life. Based on research in the field it is proposed here how, once a self-replicating genetic molecule existed, life might have started and gradual evolution of complexity was made possible ...”

    in other words, the first life required none of the complexity of modern life.

    “...Later research had cast doubt on the existence of a reducing atmosphere, and suggested a neutral atmosphere instead – see also (Chyba 2005), the accompanying article to Tian et al. (see below).
     
    However, new calculations indicate that hydrogen escaped from the early atmosphere at a much slower rate than previously thought, yielding an atmosphere where hydrogen was a major component (about 30 😵 and which was therefore highly reducing (Tian et al. 2005 , see also press release). ...”

    the reason why the above is relevant is because a reducing atmosphere favours the right kind on chemistry for abiogenesis.

    “...For a long time the synthesis of RNA monomers under prebiotic conditions appeared to be a fundamental problem since the condensation of sugar (ribose) and nucleobase (purines and pyrimidines) does not work (Orgel, 2004). The prebiotic synthesis of purine ribonucleotides is still unclear, yet recently a breakthrough has been made with regard to the synthesis of pyrimidine ribonucleotide monomers (which incorporate cytosine and uracil). It now appears in principle to be solved, in a completely unexpected manner. ...”

    -and it then goes on to explain how.

    Here are two more extracts:

    “...The group of David Deamer has shown that the synthesis of RNA-like polymers can even occur from non-activated mononucleotides within phospholipids vesicles, due to the chemical potential of fluctuating anhydrous and hydrated conditions, with heat providing activation energy during rehydration (Rajamani et al. 2008). Such conditions could have existed around hot springs on the prebiotic Earth. The lipids also provide a structurally organizing microenvironment that imposes order on mononucleotides. In this experimental setup, oligomers of up to 100 nucleotides can be formed non-enzymatically. It remains to be seen if prebiotically plausible fatty acid vesicles could have the same effect on RNA synthesis (with this a self-replicating RNA molecule would also have been pre-packaged for further evolution, cf. below). Effective polymerization of monomers that are activated might be aided by a structurally organizing microenvironment within vesicles as well. ...”

    “...Extrapolating from all the above data, inside fatty-acid vesicles the first self-replicating RNA molecule could have started copying itself. During copying, various things would have been possible. High-fidelity copies would have yielded the same self-replicating molecule. Copies with errors would mostly have resulted in RNA that was non-functional, but in a minority of cases, they could have yielded RNA that copied itself faster. It has been shown (Chen et al. 2004, see also news article) that RNA/vesicle systems that contain more genetic material (which would have resulted from faster RNA replication) develop more internal tension than neighboring vesicles that do not contain as much RNA, and draw membrane material from them. Importantly, this would have allowed for natural selection of vesicles by competition even in the absence of the ability to synthesize their own membrane components and therefore to directly control their own growth. Thus, for the first time, a system would have had the ability to undergo Darwinian evolution by natural selection acting on variation. This would have been a new and crucial emergent property arising at the transition from non-life to life. ...”

    I have to admit I haven't read all of it yet as it's a rather long article but my overwhelming impression is they really have, surprisingly, either got the worst if it pretty much worked out or at least they soon will have.
  2. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
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    28 Feb '11 17:22
    Originally posted by Andrew Hamilton
    I was curious to know just how far scientists have got with abiogenesis research thinking it was such a difficulty subject that it would be very difficulty for them to get far on it but I was surprised to find just how far they have managed to go albeit with still many unanswered questions and gaps in our knowledge. I found this link:

    http://www.t ...[text shortened]... rprisingly, either got the worst if it pretty much worked out or at least they soon will have.
    It can be taken as a matter of course the creationist/intelligent design crowd would reject this work.

    I just started watching a show called Into the wormhole, narrated by Morgan Freeman
    and in one of the episodes, talked about this same thing, although on a much simplified basis. The experiment shown on the show was simulating the early reducing atmosphere in a quartz flask that was continually shaken to simulate waves crashing on a beach and introducing simple sugars and amino acids and it was shown for the two to reach a point where the sugar and the amino acid joined up as the first link in the RNA chain, a one vertebrae piece of RNA so to speak.

    Does the work shown in your report go beyond that? Linking more single units to longer RNA strands?

    Into the wormhole is a really great show, all about the big questions in science, quantum mechanics, origin of life, time travel and other subjects. You ever hear of it? Morgan Freeman is the executive producer so he must have a deep interest in science. Best show on popularizing science since Carl Sagan's Cosmos and Jacob Bronowski's Ascent of man.

    I just found out you can get all 13 episodes of the Ascent of Man for about 100 bucks here:

    http://www.ambrosevideo.com/items.cfm?id=860
  3. Cape Town
    Joined
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    28 Feb '11 19:32
    Originally posted by sonhouse
    I just found out you can get all 13 episodes of the Ascent of Man for about 100 bucks here:

    http://www.ambrosevideo.com/items.cfm?id=860
    They're ripping you off:

    http://www.amazon.co.uk/Ascent-Man-Complete-BBC-DVD/dp/B000772842

    even here in SA we can get it for the equivalent of about US$ 70

    http://www.take2.co.za/dvd-the-ascent-of-man-4-disc-boxset-478688.html

    (though I see it currently isn't in stock)
  4. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
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    28 Feb '11 21:40
    Originally posted by twhitehead
    They're ripping you off:

    http://www.amazon.co.uk/Ascent-Man-Complete-BBC-DVD/dp/B000772842

    even here in SA we can get it for the equivalent of about US$ 70

    http://www.take2.co.za/dvd-the-ascent-of-man-4-disc-boxset-478688.html

    (though I see it currently isn't in stock)
    Ah, Ambrose bought all their stock🙂
  5. Joined
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    01 Mar '11 16:38
    Originally posted by sonhouse
    It can be taken as a matter of course the creationist/intelligent design crowd would reject this work.

    I just started watching a show called Into the wormhole, narrated by Morgan Freeman
    and in one of the episodes, talked about this same thing, although on a much simplified basis. The experiment shown on the show was simulating the early reducing atmos ...[text shortened]... of the Ascent of Man for about 100 bucks here:

    http://www.ambrosevideo.com/items.cfm?id=860
    “...Does the work shown in your report go beyond that? Linking more single units to longer RNA strands? ..”

    I think so but I am not sure because it refers to “RNA-like polymers” which I assume is the same thing as “RNA strands”?
    It says:

    “...The group of David Deamer has shown that the synthesis of RNA-like polymers can even occur from non-activated mononucleotides within phospholipids vesicles, due to the chemical potential of fluctuating anhydrous and hydrated conditions, with heat providing activation energy during rehydration (Rajamani et al. 2008). Such conditions could have existed around hot springs on the prebiotic Earth. ...”

    and then it says a few bits more about that.
  6. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
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    01 Mar '11 20:451 edit
    Originally posted by Andrew Hamilton
    “...Does the work shown in your report go beyond that? Linking more single units to longer RNA strands? ..”

    I think so but I am not sure because it refers to “RNA-like polymers” which I assume is the same thing as “RNA strands”?
    It says:

    “...The group of David Deamer has shown that the synthesis of RNA-like polymers can even occur from non-act ...[text shortened]... around hot springs on the prebiotic Earth. ...”

    and then it says a few bits more about that.
    On Into the wormhole, the actual scientist involved in the RNA synthesis research was named, I didn't copy his name down, they mention the names of a lot of scientists, I'll try to find it on the next rerun and see who it is and what university he works at.

    Don't quote me on this but I think it is actual RNA structure, the first bit anyway, not RNA-like polymers.

    Outside of the recent and contentious discovery of arsenic incorporating DNA, why is it DNA and RNA is the only shape we have in our lifeforms on Earth?

    It would seem if there were competing shapes that would work, maybe there would be some remnant around. Of course it could be here but so rare we just have not run into it yet.

    Wouldn't it be a gas if a couple hundred years from now, we have gone to most of the moons and hard planets and discover life, say, on Europa, and discover it is based on the same thing, our version of RNA and DNA.

    That would say a whole lot about what life might be like on say, Alpha Centauri planets or moons, eh. I mention that star because it so far appears like both our sun and Alpha's came from the same cauldron.

    There was an article a few months back in Sci Am about the stars that were made at the same time as Sol and it turns out they can track them, they were all part of the same cluster millions of years ago but they have slowly spread out over thousands of light years of our spiral arm of the milky way, but it would seem for one of those suns to be the best bet for Earthy kind of life.
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