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A Substantial Conundrum Confronting The Chemical Origin Of Life

In ID circles we often discuss the sheer rarity of biologically relevant polypeptides with respect to combinatorial sequence space (and the related conundrum of macromolecular interdependence). It has often been argued that this represents a potent challenge to chemical origin-of-life models of an order substantially greater than the challenge it presents to biological evolution. There is one related problem in this regard which is often overlooked, and I want to briefly explore it in this blog entry.

When it comes to polymerization of amino acids to form proteins, two things must be borne in mind with regards to the formation of peptide bonds.

  1. Peptide bond formation is an endothermic reaction. This means that the reaction requires the absorption of energy: It does not take place spontaneously.
  2. Peptide bond formation is a condensation reaction. It hence involves the net removal of a water molecule. So not only can this reaction not happen spontaneously in an aqueous medium, but, in fact, the presence of water inhibits the reaction.

There is also the added problem of interfering cross-reactivity (the probability of interfering cross-reactions between the chemical groups on the various amino acid side chains is quite high).

But this is only the peak of the proverbial ice berg. The difficulties associated with synthesizing peptides (altogether with appropriate homochirality and all) are only half the story. There is also the problem of breaking the peptide bonds in order to generate a range of amino acid sequences in view of finding some with meaningful activity. I mentioned previously that the formation of a peptide bond requires a loss of a water molecule and the input of energy. On the flip side of the coin, then, breaking these bonds requires the addition of a water molecule and involves an energetically favorable reaction. But here’s the thing: Although this entails a net release of energy, the reaction involves high activation energy. But the activation energy for hydrolysis of peptide bonds is such that spontaneous hydrolysis under ambient conditions is not something which occurs readily.

In view of the difficulties associated with the making and breaking of peptide bonds, a very bleak picture is painted for the exploration of amino acid sequences in the pre-biotic context. Given that the conditions required for the making and breaking of peptide bonds are really quite different from one another, if naturalistic origin-of-life scenarios are to have any traction, it would entail that a location be required in which the conditions can vary significantly, alternating between conditions suitable for peptide bond formation and breaking. And this of course is compounded by the fact that the reactions, when they do occur, are likely to be slow and inefficient. Even granting that volcanoes and ocean vents might have provided the necessary changing conditions, it still stands to reason that the production of different polypeptides cannot have exceeded the rate of change of environmental conditions. This would dramatically limit the potential number of polypeptides which could have been produced in the prebiotic world, thus placing considerable restraints on the probabilistic resources at one’s disposal for the formation of multiple biologically relevant (and functionally interdependent) polypeptides.

In view of the reasons articulated above (and many others), the proteins-first model of the origin of life may be taken as essentially dead in the water. Not only are there the substantive challenges of even forming biologically relevant polypeptides. But even supposing that such prebiotic polymers could be produced in this way and useful sequences were happened across, the polymyers have to be able to reproduce with reasonable integrity. But there does not appear to be any way in which a polypeptide can determine a peptide sequence in some fashion analogous to that of base pairing of nucleic acids. How would these proteins be replicated in order to facilitate the workings of natural selection?

In view of the obvious closed-loop “catch-22″ paradox of DNA making proteins and proteins making DNA, there is, of course, the fashionable scenario of the RNA world: That is to say, the possible role of RNA as the earliest hereditary macromolecule. This is seen to follow from the realization that RNA not only has information-carrying capacity, but also possesses catalytic capability. Proposed evidence for this notion included the fact that RNA makes up a large proportion of ribosomes (the protein factory of the cell). Furthermore, in eukaryotes (organisms with nucleated cells), components of genes which don’t code for proteins (called “introns”) are spliced out of an RNA transcript before translation. RNA molecules are involved in many of the RNA-splicing processes, and it has been documented that some RNA introns have self-splicing capability: that is to say, they can excise themselves, though at a slower rate than proteins can do it. Further observations which were taken as evidence for the plausibility of the RNA world thesis included the existence of RNA viruses, which use RNA as their genetic material which is translated directly into proteins.

Leaving aside the problems of attaining an RNA-based replicase (for that discussion, see Signature in the Cell), the problem is that the difficulties outlined above with regards the formation of polypeptides are really quite trivial in comparison to the difficulty of obtaining polynucleotides, in part because of the different kinds of bonds which need to be made and broken and the very different reaction conditions which are necessary at each stage. Nucleotides are composed of three chemical subunits – a ribose sugar, a phosphate group, and a nitrogenous base. Not only do these components need to be present and react together in an appropriate fashion in order to produce one nucleotide, but these nucleotides then have to be polymerized, a process which requires a series of endothermic condensation reactions, thereby requiring a high-energy condensing agent in order to perform them. In order to obtain nucleosides (i.e. base and ribose), one would need to begin with a mixture of nitrogenous bases and ribose and an appropriate condensing agents. To obtain nucleotides requires the mixing of nucleosides with phosphate and a different condensing agent.

The scenario for self-replicative capability of polynucleotides is more optimistic than that for polypeptides. But this is by no means trivial. At the heart of Darwinian rationale lies the concept that evolution must strike a balance between reliable reproduction of a species on the one hand, and opportunistic variation on the other. A poor replicator is much more likely to degrade through inaccurate copying than to be enhanced by evolution. There thus exists a threshold before the cumulative improvement of a replicator can occur by selection. A replicator must already have a reasonably good performance before it can even improve on that performance. At this point, however, we are running perilously close to yet another catch-22 conundrum: If (as I think is a legitimate assumption), this threshold performance level may be only attained with a sequence substantially longer than the minimum required for folding, one is faced with the even greater improbabilities of attaining such a replicator by a blind search.

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40 Responses to A Substantial Conundrum Confronting The Chemical Origin Of Life

  1. JM:

    Excellent summary!

    GEM of TKI

    PS: Care to say a few words on the implications of the chirality problem?

  2. Thank you very much for your article, JonathanM. It lends a valuable perspective to the contemporary discussion of origin-of-life scenarios.

    By the way, what are your thoughts on this latest offering from “New Scientist”, on RNA-based replicators?

    http://www.newscientist.com/ar.....cator.html

  3. Yockey comments on chirality. From Information Theory, Evolution, and the Origin of Life.

    1.1.1 It (chirality) can serve as a definition of life, as any substance composed of only one optical isomer must have come from life.

    8.1.3 Protein is composed of L-alpha amino acids, except glycine that is symmetric; sugars in DNA and RNA are dextro. But those compounds, if they were in the Urshcleim, would have been racemic, composed of equal amounts of each handedness. Could abiotic chemical evolution select only the L-Amino acids and only the dextro sugars leading to complex sequences and to life by abiological chemical evolution?

    cont…

    As Louis Pasteur (Pasteur, 1848, 1922) showed in 1848, life is the only means capable of selecting molecules of only one-handedness.

    cont…

    All speculation on the origin of life on Earth by chance can not survive the first criterion of life: proteins are left-handed, sugars in DNA and RNA are right-handed. Omne vivum ex vivo. Life must come only from life.

  4. Asking me to believe that proteins somehow arose independently of any system of encoding and then those proteins just managed to get encoded in DNA is asking me to believe in miracles.

  5. Indeed. One needn’t really calculate the probability of dealing oneself a royal flush at the core of the Sun. Factors other than playing-card combinatorics will tend to dominate in such an instance. It is the same with biomolecular reaction kinetics.

  6. Nice clip TGP. Excellent point.

  7. Thanks for the post. Lots of good stuff to think about. Abiogenesis is not just in need of a few details to be worked out, but runs smack into irreconcilable difficulties at every turn. I think the question about whether abiogenesis can occur is a valid scientific question. Based on our current understanding, however, the idea that abiogenesis actually can occur in practice is, perhaps, not even a scientifically tenable position for someone to take. I appreciate you pointing out one more nuance that isn’t often discussed.

    In your last paragraph you talked about a minimal replicator. Can anyone point me to such a thing as a self-replicating molecule? (Mung, crystals don’t count.)

    What would a minimal replicator need to have? It seems to me it would need to be a relatively sophisticated piece of machinery, certainly with more than one part. Is there any rational basis for thinking that reliable replication machinery can be much more simple than what we currently see in the cell?

  8. Not only do these components need to be present and react together in an appropriate fashion in order to produce one nucleotide, but these nucleotides then have to be polymerized, a process which requires a series of endothermic condensation reactions, thereby requiring a high-energy condensing agent in order to perform them. In order to obtain nucleosides (i.e. base and ribose), one would need to begin with a mixture of nitrogenous bases and ribose and an appropriate condensing agents. To obtain nucleotides requires the mixing of nucleosides with phosphate and a different condensing agent.

    Dude! Read up on the latest chemistry before saying such silly things!!

    http://www.nature.com/news/200.....9.471.html

    RNA world easier to make

    Ingenious chemistry shows how nucleotides may have formed in the primordial soup.

    Richard Van Noorden

    An elegant experiment has quashed a major objection to the theory that life on Earth originated with molecules of RNA.

    John Sutherland and his colleagues from the University of Manchester, UK, created a ribonucleotide, a building block of RNA, from simple chemicals under conditions that might have existed on the early Earth.

    The feat, never performed before, bolsters the ‘RNA world’ hypothesis, which suggests that life began when RNA, a polymer related to DNA that can duplicate itself and catalyse reactions, emerged from a prebiotic soup of chemicals.

    “This is extremely strong evidence for the RNA world. We don’t know if these chemical steps reflect what actually happened, but before this work there were large doubts that it could happen at all,” says Donna Blackmond, a chemist at Imperial College London.
    Molecular choreography

    An RNA polymer is a string of ribonucleotides, each made up of three distinct parts: a ribose sugar, a phosphate group and a base — either cytosine or uracil, known as pyrimidines, or the purines guanine or adenine. Imagining how such a polymer might have formed spontaneously, chemists had thought the subunits would probably assemble themselves first, then join to form a ribonucleotide. But even in the controlled atmosphere of a laboratory, efforts to connect ribose and base together have met with frustrating failure.

    The Manchester researchers have now managed to synthesise both pyrimidine ribonucleotides. Their remedy is to avoid producing separate ribose-sugar and base subunits. Instead, Sutherland’s team makes a molecule whose scaffolding contains a bond that will turn out to be the key ribose-base connection. Further atoms are then added around this skeleton, which unfurls to create the ribonucleotide.

    The final connection is to add a phosphate group. But that phosphate, although only a reactant in the final stages of the sequence, influences the entire synthesis, Sutherland’s team showed. By buffering acidity and acting as a catalyst, it guides small organic molecules into making the right connections.

    “We had a suspicion there was something good out there, but it took us 12 years to find it,” Sutherland says. “What we have ended up with is molecular choreography, where the molecules are unwitting choreographers.” Next, he says, he expects to make purine ribonucleotides using a similar approach.

    ID — yes, it’s a God-of-the-gaps argument, but even worse, it’s very often not a God-of-the-gaps-in-human-knowledge argument, it’s a God-of-the-gaps-in-IDist-knowledge argument.

    Nick

    PS1: Re: early amino acid sequences. IDists/creationists never take into account relevant facts like:

    - prebiotic amino acids were not an equal mix of 20 modern amino acids. They were likely mostly glycine (which is achiral) and some hydrophobic amino acids.

    - the first functional polypeptide used by the RNAworld or some precursor is not thought to be a fully-functioning modern enzyme. It was probably just a cofactor in a reaction, or a short polypeptide with a function like “being hydrophobic and sticking to a membrane”. The chirality and sequence-specificity can come about gradually later, they do not have to all be solved at once at the very beginning.

    PS2: Regarding Jonathan M’s arguments about chemical reactions — no chemist would take these seriously. First of all, even creationists typically argue that polymers in aqueous solution degrade spontaneously, particularly at warmer temperatures. Yes, this happens faster if there are catalytic enzymes around to lower the activation energy, but it happens regardless. Apart from just generic spontaneous degradation, the whole ocean apparently passes through the cookers of the seafloor spreading zones over a relatively short geological timescales (10 my or less IIRC), so no one holds that polymers would gradually build up in the global ocean over millions of years.

    If JonathanM actually wants to discuss what actual scientists actually think instead of just happily imagining that scientists are morons who haven’t thought things through, the place to look is various natural traps that would raise the concentration of monomers relative to water. Suggestions include fine porous systems, drying pools at the surface and under rocks or below ground, and the same but in freezing systems. All of these effectively remove liquid water and thus enable the formation of polymers. Ice, in particular, also helps slow the reverse reaction of degradation to monomers.

    And it’s not like cyclical variants on the above traps are hard to find, not a planet that has day/night cycles, seasonal cycles, and orbital variations.

    Also, it’s ridiculous to portray the above as optimistic special pleading. Over here in reality-land, it’s blindingly obvious that an almost uncountable number of these traps would occur on any sterile planet that is (a) round, and therefore has warm parts and cold parts, (b) has water and (c) has land.
    Why should scientists take you guys seriously if you can’t get the absolute basics right, and if the pro-ID commentators can’t be bothered to make the obvious corrections either? The core reason scientists dislike ID is its overwhelming tendency to claim that a paradigm-shattering scientific revolution should happen, based on extremely poorly-researched, mistake-filled, amateurish-in-a-bad-way arguments about science that IDists don’t understand and can’t be bothered to learn about.

  9. //ID — yes, it’s a God-of-the-gaps argument//

    Sigh, we don’t conclude design because the Darwinist has failed to explain p invoking heroic material causes, no more than archaeologists conclude design simply because the naturalist has failed to explain the artifacts by invoking sand storms and erosion. We conclude design independently of the Darwinist’s heroic explanations, therefore it cannot be a gap, it’s not that you don’t have an argument. You can have an argument too for how mount rushmore’s pattern formed naturally, but this would make no difference to our design inference for the pattern on mount rushmore.

    //The feat, never performed before, bolsters the ‘RNA world’ hypothesis, which suggests that life began when RNA, a polymer related to DNA that can duplicate itself and catalyse reactions//

    lol, I laughed when I saw this, “RNA a polymer related to DNA that can duplicate itself”

    Douglas Axe comments on the experiment that “demonstrated” how RNA can replicate itself:

    “The humble truth is that the catalytic RNAs simply join two pre-made halves together by making a single new chemical bond. [2] What’s more, the molecular structure for accomplishing this joining is built into the precursors in such a way that 1) wrong ends cannot be joined, and 2) the energy for the correct joining is pre-supplied”

    But who cares about the details anyway? the Darwinist already “knows”(in his heart) life *had* to evolve one way or another right?

    //Their remedy is to avoid producing separate ribose-sugar and base subunits. Instead, Sutherland’s team makes a molecule whose scaffolding contains a bond that will turn out to be the key ribose-base connection. Further atoms are then added around this skeleton, which unfurls to create the ribonucleotide.

    The final connection is to add a phosphate group. But that phosphate, although only a reactant in the final stages of the sequence, influences the entire synthesis//

    “remedy”, ” team makes molecule” “final connection” Intelligent design(interference) is written all over this, it’s a mess, no seriously you cant make this stuff up.

  10. 10

    Again reference to the soup theory in Nick’s paper:

    2009: “a polymer related to DNA that can duplicate itself and catalyse reactions, emerged from a prebiotic soup of chemicals.”

    Except that:

    2010: “New research rejects 80-year theory of ‘primordial soup’ as the origin of life”

    http://www.physorg.com/news184336191.html

  11. Nick, I didn’t know the earth, being round, thus allowing for variable climate is all the evidence one needs to show that an RNA first world is possible, thus ‘naturally’ inevitable.

    But then again, this type of shoddy logic is probably why design deniers like yourself are being successfully challenged in the marketplace of ideas as well as in the lab.

    Eh, jus’ curious. Do you have a lab, Nick? Or work in one, anyway?

  12. Nick: I am an organic chemist and keep up with origin-of-life chemistry pretty well. In my opinion, the scraps of evidence for a chemical origin of life are light years from any plausible scenario. May I remind you that one of the world’s OOL experts, George Whitesides of the Harvard OOL project says he has “no idea” how life could have gotten started (see http://pubs.acs.org/cen/covers.....over1.html, and scroll halfway down). Although as an atheist he believes OOL somehow happened, he finds all the theories implausible, including your favorite “RNA world” one. The magnitude of the problem (cellular complexity) has been growing rapidly for decades, while the “evidence” has been the straws a drowning materialist grasps at.

    The fact is that people who believe in a chemical OOL do so on philosophical grounds, not scientific ones. Whitesides is an honest materialist, honest enough (and secure enough) to call out the inadequacy of even his favorite notions.

  13. Carl Sagan said “Extraordinary claims require extraordinary evidence”, and he was right about that.

    Life-from-chemicals is a very extraordinary claim.

    Nick, would you say that the Miller-Urey and Sutherland experiments, along with the bits and pieces others have contributed, amount to “extraordinary evidence”?

  14. “Instead, Sutherland’s team makes a molecule whose scaffolding contains a bond that will turn out to be the key ribose-base connection. Further atoms are then added around this skeleton, which unfurls to create the ribonucleotide.”

    Did this happen spontaneously without intervention, or were the researchers carefully guiding and intervening to make this happen? It is hard to tell from this description.

    I note that Shapiro, in the linked news article, was singularly unimpressed.

  15. 15

    Hmm, no one is willing to admit Jonathan M made a straight-up mistake in claiming a “conundrum” for a problem that, in fact, doesn’t exist in the latest, very well-known work? This is another reason ID gets no cred in science. Its proponents circle the wagons and change the subject rather than admit a mistake.

  16. Our friend Nick writes:

    //This is another reason ID gets no cred in science.//

    vs the Philosopher of science Lakatos:

    “Scientists have thick skins. They do not abandon a theory [merely] because facts contradict it. They normally either invent some rescue hypothesis to explain what they then call a mere anomaly and if they cannot explain the anomaly, they ignore it, and direct their attention to other problems.”

    I think Darwinian logic can be summed up like this: life looks designed because it’s not.

  17. Steve,

    I’m really curious about this. Considering that evolutionary principles and basic chemical principles (such as those used in Miller-Urey and the several thousand replications of Miller-Urey) are used in literally thousands of biological, chemical, economic, financial, engineering, computer science, process, and medical research programs, income based businesses, and important advances that many humans use on a daily basis all over the world…

    I would really like some evidence that any of this is being challenged in the ‘marketplace of ideas’ by ID.

    Can you name one tool, process, or product that is a direct result of the principles of ID (as promoted here on UD)?

  18. Nickmatzke,

    Even if ID-ers were doing what you allege, don’t you see that you are DOING THE EXACT SAME THING? I mean, did you even read what Polyani wrote?

    And also, I’m extremely skeptical of scientific reports where scientists are commenting on their own research touting how it’s extremely strong evidence for whatever. Let neutral scientists comment on it and let’s see what they say.

  19. Collin,

    “I’m extremely skeptical of scientific reports where scientists are commenting on their own research touting how it’s extremely strong evidence for whatever. Let neutral scientists comment on it and let’s see what they say.”

    Why don’t you read the actual scientific research papers, that have already been commented on by a number of scientists other than the authors?

  20. “Douglas Axe comments on the experiment that “demonstrated” how RNA can replicate itself:
    “The humble truth is that the catalytic RNAs simply join two pre-made halves together by making a single new chemical bond. [2] What’s more, the molecular structure for accomplishing this joining is built into the precursors in such a way that 1) wrong ends cannot be joined, and 2) the energy for the correct joining is pre-supplied””

    Yes, right, I forgot: unless a researcher can show how an event X could happen in an unbroken chain of events from the Big Bang on, their research results are worthless. What a bizarre view of science. The research showed how a specific event, that had been a conundrum before, could happen. A number of the precursor steps have already been shown to be possible / likely / provided for in the presumed conditions. Some are not yet. And in a research lab led by Polanyi, using assumptions that haven’t been proven yet as ramifications for an experiment is apparently verboten. Good luck getting any research done, Polanyi.

    ““remedy”, ” team makes molecule” “final connection” Intelligent design(interference) is written all over this, it’s a mess, no seriously you cant make this stuff up.”

    Seriously? You take the terminology used in a report about a research paper to claim that the conclusions of the research are “a mess”?

  21. As Louis Pasteur (Pasteur, 1848, 1922) showed in 1848, life is the only means capable of selecting molecules of only one-handedness.

    Excellent point, but unfortunately, untrue. He showed quite the opposite.

  22. Nick, the experiment you cite do not represent plausible natural occcurences. The experiment is intelligently designed to produce the desired products:

    http://www.arn.org/blogs/index.....l_of_the_w

    http://crev.info/content/origi.....st_nothing

  23. Nick:

    Yes, actually I mention the paper you cite in a forthcoming blog entry concerning the recent article in New Scientist about the RNA World.

    Stephen Meyer said it well:

    …Powner and colleagues only partially addressed the problem of generating the constituent building blocks of RNA under plausible pre-biotic conditions. The problem, ironically, is their own skillful intervention. To ensure a biologically-relevant outcome, they had to intervene–repeatedly and intelligently–in their experiment: first, by selecting only the right-handed isomers of sugar that life requires; second, by purifying their reaction products at each step to prevent interfering cross-reactions; and third, by following a very precise procedure in which they carefully selected the reagents and choreographed the order in which they were introduced into the reaction series.
    Thus, not only does this study not address the problem of getting nucleotide bases to arrange themselves into functionally-specified sequences, but the extent to which it does succeed in producing biologically-relevant chemical constituents of RNA actually illustrates the indispensable role of intelligence in generating such chemistry.

    J

  24. Nick: “. . . a problem that, in fact, doesn’t exist in the latest, very well-known work?”

    Oh, boy. I hope you’re not referring to the Sutherland work you cited? No problem exists; we’ve got it all under control; nothing to see here folks; move along . . .

  25. 25

    Cmon guys, JonathanM argued the following:

    Nucleotides are composed of three chemical subunits – a ribose sugar, a phosphate group, and a nitrogenous base. Not only do these components need to be present and react together in an appropriate fashion in order to produce one nucleotide, but these nucleotides then have to be polymerized, a process which requires a series of endothermic condensation reactions, thereby requiring a high-energy condensing agent in order to perform them. In order to obtain nucleosides (i.e. base and ribose), one would need to begin with a mixture of nitrogenous bases and ribose and an appropriate condensing agents. To obtain nucleotides requires the mixing of nucleosides with phosphate and a different condensing agent.

    …and it was directly falsified by Sutherland’s work back in 2009. I’m not saying Sutherland solved all questions about the origin of life, or that all questions are answered. I’m just saying that one of JonathanM’s arguments was blatantly wrong and uninformed to boot (well, several others were as well, but I’m not addressing those in this comment). In science you are supposed to admit mistakes, if you don’t, well then, you’re not doing science, you’re doing propaganda.

  26. Nick [17]:

    At New Scientist they have an article giving an overview of the RNA world hypothesis. They mention Sutherland’s work.

    It said something like Sutherland took “half a base, half a ribose” and got them to combine, and that he had phosphorous present from the beginning. I would suspect that to get a “half of a sugar, and half of a base” requires some kind of lab set-up. Is it then feasible to think such segregating mechanisms were present somewhere on the earth? I would severely doubt it.

    So your claim that JohnnyM is “wrong” requires a huge kind of caveat. You, yourself, said: “I’m not saying Sutherland solved all questions about the origin of life . . .” Well, you could have, and probably should have, said: “I’m not saying Sutherland solved all questions about the mechanism whereby RNA nucleotides can form freely in nature….” But, of course, this would be to backtrack on your charge.

  27. I wonder why Nick hasn’t commented on this…

  28. 28

    Indeed. So true.

  29. And as it happens I have a blog post on this very topic going up first thing tomorrow morning on Evolution News & Views.

    J

  30. Carl Sagan said “Extraordinary claims require extraordinary evidence”, and he was right about that.

    Actually, he wasn’t right.

  31. “One day soon, Sutherland says, someone will fill a container with a mix of primordial chemicals, keep it under the right conditions, and watch life emerge.”
    New Scientist 2011 http://www.newscientist.com/ar.....tml?page=3

    These people are seriously deluded.

  32. I’ll certainly be looking into it!;) Thanks for alerting me.

  33. Start up a blog, challenge Darwinism, and watch the IDiots emerge?

  34. 34
    material.infantacy

    Dude! Read Jonathan M’s latest article:
    http://www.evolutionnews.org/2.....49621.html

  35. So how does ID explain the origin of life?

  36. 36

    It said something like Sutherland took “half a base, half a ribose” and got them to combine, and that he had phosphorous present from the beginning. I would suspect that to get a “half of a sugar, and half of a base” requires some kind of lab set-up. Is it then feasible to think such segregating mechanisms were present somewhere on the earth? I would severely doubt it.

    Why suspect, when you can look it up with a simple google search?

    The Sutherland Group at the School of Chemistry, University of Manchester have demonstrated high yielding routes to cytidine and uridine ribonucleotides built from small 2 and 3 carbon fragments such as glycolaldehyde, glyceraldehyde or glyceraldehyde-3-phosphate, cyanamide and cyanoacetylene.

    Calling these “half a sugar” or “half a base” isn’t inaccurate but it’s oversimplifying, as journalists do. It implied there is something unique and special about these compounds. In reality, these are just small, quite simple molecules that will occur when you add energy to a reducing environment with N and C in it. Like in Titan’s atmosphere:

    http://www.google.com/search?h.....8;ie=UTF-8

    As for segregating mechanisms, the natural world is full of them, and it’s not clear how much in terms of segregating mechanisms would be needed for Sutherland’s pathway anyway. Certainly it needs much less segregation than a simple-minded “build a ribose, then build a base, then bring them together with phosphate” pathway would.

  37. It doesn’t.

    Recently it was pointed out to me here that ID only draws design inferences from objects that we can directly study. First life is unavailable for direct study, therefore ID has nothing scientific to say about it.

    When ID supporters do speculate on the origin of life they are engaging in mataphysics, not science.

    At least that is what I took away from my conversations with Barry Arrington.

    fG

  38. Extraordinary claims require extraordinary ADEQUATE evidence.

  39. FG

    You have been corrected on your direct and implied errors in the above many times, but have simply ignored correction.

    A note for record.

    GEM of TKI

  40. Onlookers, cf here, in context and the onward links.

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