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Thread: Advances in Chirality and other problems of abiogenesis in the Origins of Life

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    tWebber shunyadragon's Avatar
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    Advances in Chirality and other problems of abiogenesis in the Origins of Life

    One of the frequent challenges of abiogenesis by ID advocates and other fundamentalist creationists is the problem of the necessity of Chirality in life. The simple answer is yes, Chirality is necessary and did develop with the abiogenesis and the origins of life. The challenge by the IDers is that Chirality is Extremely unlikely, Arguing from ignorance is the achille's heal many ID arguments, because science often determines with research is possible and even likely.

    The following is a very plausible process of how Chirality can come about naturally.

    Source: https://scitechdaily.com/the-chiral-puzzle-of-life-cosmic-rays-may-have-left-indelible-imprint-on-early-life/



    The Chiral Puzzle of Life: Cosmic Rays May Have Left Indelible Imprint on Early Life

    TOPICS:AstrobiologyAstrophysicsStanford University

    By TAYLOR KUBOTA, STANFORD UNIVERSITY MAY 20, 2020

    Physicists propose that the influence of cosmic rays on early life may explain nature’s preference for a uniform “handedness” among biology’s critical molecules.

    Before there were animals, bacteria or even DNA on Earth, self-replicating molecules were slowly evolving their way from simple matter to life beneath a constant shower of energetic particles from space.

    In a new paper, a Stanford professor and a former post-doctoral scholar speculate that this interaction between ancient proto-organisms and cosmic rays may be responsible for a crucial structural preference, called chirality, in biological molecules. If their idea is correct, it suggests that all life throughout the universe could share the same chiral preference.

    Chirality, also known as handedness, is the existence of mirror-image versions of molecules. Like the left and right hand, two chiral forms of a single molecule reflect each other in shape but don’t line up if stacked. In every major biomolecule – amino acids, DNA, RNA – life only uses one form of molecular handedness. If the mirror version of a molecule is substituted for the regular version within a biological system, the system will often malfunction or stop functioning entirely. In the case of DNA, a single wrong handed sugar would disrupt the stable helical structure of the molecule.

    Louis Pasteur first discovered this biological homochirality in 1848. Since then, scientists have debated whether the handedness of life was driven by random chance or some unknown deterministic influence. Pasteur hypothesized that, if life is asymmetric, then it may be due to an asymmetry in the fundamental interactions of physics that exist throughout the cosmos.

    “We propose that the biological handedness we witness now on Earth is due to evolution amidst magnetically polarized radiation, where a tiny difference in the mutation rate may have promoted the evolution of DNA-based life, rather than its mirror image,” said Noémie Globus lead author of the paper and a former Koret Fellow at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).

    In their paper, published today (May 20, 2020) in Astrophysical Journal Letters, the researchers detail their argument in favor of cosmic rays as the origin of homochirality. They also discuss potential experiments to test their hypothesis.

    Magnetic polarization from space
    Cosmic rays are an abundant form of high-energy radiation that originates from various sources throughout the universe, including stars and distant galaxies. After hitting the Earth’s atmosphere, cosmic rays eventually degrade into fundamental particles. At ground level, most of the cosmic rays exist only as particles known as muons.

    Muons are unstable particles, existing for a mere 2 millionths of a second, but because they travel near the speed of light, they have been detected more than 700 meters below Earth’s surface. They are also magnetically polarized, meaning, on average, muons all share the same magnetic orientation. When muons finally decay, they produce electrons with the same magnetic polarization. The researchers believe that the muon’s penetrative ability allows it and its daughter electrons to potentially affect chiral molecules on Earth and everywhere else in the universe.

    “We are irradiated all the time by cosmic rays,” explained Globus, who is currently a post-doctoral researcher at New York University and the Simons Foundation’s Flatiron Institute. “Their effects are small but constant in every place on the planet where life could evolve, and the magnetic polarization of the muons and electrons is always the same. And even on other planets, cosmic rays would have the same effects.”

    The researchers’ hypothesis is that, at the beginning of life on Earth, this constant and consistent radiation affected the evolution of the two mirror life-forms in different ways, helping one ultimately prevail over the other. These tiny differences in mutation rate would have been most significant when life was beginning and the molecules involved were very simple and more fragile. Under these circumstances, the small but persistent chiral influence from cosmic rays could have, over billions of generations of evolution, produced the single biological handedness we see today.

    “This is a little bit like a roulette wheel in Vegas, where you might engineer a slight preference for the red pockets, rather than the black pockets,” said Roger Blandford, the Luke Blossom Professor in the School of Humanities and Sciences at Stanford and an author on the paper. “Play a few games, you would never notice. But if you play with this roulette wheel for many years, those who bet habitually on red will make money and those who bet on black will lose and go away.”

    Ready to be surprised

    Globus and Blandford suggest experiments that could help prove or disprove their cosmic ray hypothesis. For example, they would like to test how bacteria respond to radiation with different magnetic polarization.

    “Experiments like this have never been performed and I am excited to see what they teach us. Surprises inevitably come from further work on interdisciplinary topics,” said Globus.

    The researchers also look forward to organic samples from comets, asteroids or Mars to see if they too exhibit a chiral bias.

    “This idea connects fundamental physics and the origin of life,” said Blandford, who is also Stanford and SLAC professor of physics and particle physics and former director of KIPAC. “Regardless of whether or not it’s correct, bridging these very different fields is exciting and a successful experiment should be interesting.”

    Reference: “The Chiral Puzzle of Life” by Noemie Globus and Roger D. Blandford, 20 May 2020, Astrophysical Journal Letters.
    DOI: 10.3847/2041-8213/ab8dc6

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    Last edited by shunyadragon; 05-29-2020 at 06:47 PM.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

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    Frank

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    Troll Magnet Sparko's Avatar
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    Your article outright says it is just speculation.

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    tWebber shunyadragon's Avatar
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    Quote Originally Posted by Sparko View Post
    Your article outright says it is just speculation.
    Actually no. It does not say this is the way Chirality is achieved, but it does present a working model, based on basic physics and organic chemistry that demonstrates how it can occur naturally. Of course, it does outline the need for further research as to what would be needed to support this hypothesis.

    You are misrepresenting what speculation is. The Evangelical Creationists are speculating that Chirality cannot occur naturally.
    Last edited by shunyadragon; 05-30-2020 at 09:50 AM.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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    See, the Thing is... Cow Poke's Avatar
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    Most of the Evangelicals I know believe very much in Charity.



    "Neighbor, how long has it been since you’ve had a big, thick, steaming bowl of Wolf Brand Chili?”

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    tWebber lee_merrill's Avatar
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    Quote Originally Posted by shunyadragon View Post
    One of the frequent challenges of abiogenesis by ID advocates and other fundamentalist creationists is the problem of the necessity of Chirality in life. The simple answer is yes, Chirality is necessary and did develop with the abiogenesis and the origins of life. The challenge by the IDers is that Chirality is Extremely unlikely, Arguing from ignorance is the achille's heal many ID arguments, because science often determines with research is possible and even likely.

    The following is a very plausible process of how Chirality can come about naturally.

    Source: https://scitechdaily.com/the-chiral-puzzle-of-life-cosmic-rays-may-have-left-indelible-imprint-on-early-life/



    The Chiral Puzzle of Life: Cosmic Rays May Have Left Indelible Imprint on Early Life



    “This is a little bit like a roulette wheel in Vegas, where you might engineer a slight preference for the red pockets, rather than the black pockets,” said Roger Blandford, the Luke Blossom Professor in the School of Humanities and Sciences at Stanford and an author on the paper. “Play a few games, you would never notice. But if you play with this roulette wheel for many years, those who bet habitually on red will make money and those who bet on black will lose and go away.”

    © Copyright Original Source

    But a little chirality is not what is required, major chirality (or even homochirality, one wrong-handed molecule in the chain spoils it) is needed.

    Blessings,
    Lee
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

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    tWebber shunyadragon's Avatar
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    Quote Originally Posted by lee_merrill View Post
    But a little chirality is not what is required, major chirality (or even homochirality, one wrong-handed molecule in the chain spoils it) is needed.

    Blessings,
    Lee
    True. So what? The research simply demonstrates how Chirality can take place naturally, and not whether is is a little or a lot.
    Last edited by shunyadragon; 05-30-2020 at 03:23 PM.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  7. #7
    tWebber shunyadragon's Avatar
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    Quote Originally Posted by lee_merrill View Post
    But a little chirality is not what is required, major chirality (or even homochirality, one wrong-handed molecule in the chain spoils it) is needed.

    Blessings,
    Lee
    The bold is a bogus claim and the supposed need for some kind of pure chirality is not demonstrated by any evidence. It simply needs to be available in the environment for the preferential selection to form early life.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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    tWebber shunyadragon's Avatar
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    Source: https://scitechdaily.com/did-life-emerge-in-the-primordial-soup-via-dna-or-rna-surprising-answer-from-new-research/



    Did Life Emerge in the “Primordial Soup” via DNA or RNA? Surprising Answer From New Research
    TOPICS:BiochemistryDNAEvolutionGenetics
    By UK RESEARCH AND INNOVATION JUNE 7, 2020

    Primordial Soup Concept

    Scientists have long debated which genetic information carrier — DNA or RNA — started life on Earth, but a new study suggests life could have begun with a bit of both. The research, led by scientists from the Medical Research Council (MRC) Laboratory of Molecular Biology (LMB), in Cambridge, shows for the first time how some of the building blocks of both DNA and RNA could have spontaneously formed and co-existed in the ‘primordial soup’ on Earth.

    The work challenges one of the leading hypotheses for the advent of life — the ‘RNA world’ theory, which arose in the 60s and has gained wide acceptance.

    Today, all known living organisms use the same genetic molecules — called nucleic acids — to store information. There are two sorts of nucleic acids: DNA and RNA. DNA encodes instructions in genes. Genes are turned into messages using RNA, which carries instructions to make proteins. Proteins can make structures and act as molecular machines.

    In the ‘RNA world’ theory, life started with RNA molecules, which can both store instructions and can act as a modest machine, potentially enabling them to self-replicate. It proposes that through evolution, life in the RNA world gave way to the era of DNA and proteins, because DNA is more stable and durable than RNA.

    In the current study, published in Nature, the researchers simulated the conditions on a primordial rocky Earth with shallow ponds in the lab. They dissolved chemicals that form RNA in water, then dried them out and heated them, then they simulated the early sun’s rays by exposing them to UV radiation.

    In this recreation of early Earth geochemistry, intermediates in the synthesis of two of the building blocks of RNA were simultaneously also converted into two of the building blocks of DNA.

    It is the first demonstration that reasonable amounts of a genetic alphabet made up of four building blocks, two for RNA and two for DNA — potentially sufficient to have encoded early life, which was far less complex than life today — may have been available on the primordial Earth.

    Professor John Sutherland from the MRC Laboratory of Molecular Biology, who led the work, says: “The RNA world hypothesis suggests that life began with RNA, before a genetic takeover occurred involving primitive biosynthetic machinery and natural selection to result in DNA.”

    “Our work suggests that in conditions consistent with shallow primordial ponds and rivulets there was a mixed genetic system with RNA and DNA building blocks co-existing at the dawn of life. This fulfills what many people think is a key precondition for the spontaneous emergence of life on Earth.”

    The team’s experiments to simulate early Earth geochemistry showed that four of the building blocks for DNA and RNA can arise from the same reagents and conditions. They produced cytidine and uridine, two of the building blocks of RNA, and deoxyadenosine, which is one of those of DNA. Deoxyadenosine was partly converted to deoxyinosine, which can take the role of another DNA building block.

    They believe that these four building blocks may have coexisted before life evolved and were the beginnings of a primitive genetic alphabet.

    Professor Sutherland adds: “The nucleic acids, RNA and DNA, are clearly related and this work suggests that they both derive from a hybrid ancestor, rather than one preceding the other.”

    “Since genetic information always flows from nucleic acids to proteins, and never in reverse — a principle called the ‘central dogma’ of molecular biology by Francis Crick — we now need to uncover how the information which can be stored and purveyed by these nucleic acids could have been first used to make to proteins.”

    Understanding the chemical origins of life is a fundamental aspect of natural science, and can inform the design of future synthetic biology.

    Dr. Megan Dowie, head of molecular and cellular medicine at the MRC commented: “This study shows that blue skies research can reveal fascinating insights into how the very beginnings of life may have emerged, and demonstrates the importance of supporting fundamental research. These underpinning discoveries in the life sciences could enable exciting future strategies for artificial biology.”

    Reference: “Selective prebiotic formation of RNA pyrimidine and DNA purine nucleosides” by Jianfeng Xu, Václav Chmela, Nicholas J. Green, David A. Russell, Mikołaj J. Janicki, Robert W. Góra, Rafał Szabla, Andrew D. Bond & John D. Sutherland,3 June 2020, Nature.
    DOI: 10.1038/s41586-020-2330-9

    © Copyright Original Source

    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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    tWebber lee_merrill's Avatar
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    Quote Originally Posted by shunyadragon View Post
    The bold is a bogus claim and the supposed need for some kind of pure chirality is not demonstrated by any evidence.
    It appears that one wrong-handed amino acid or sugar will spoil the molecule:

    Source: Reasons to Believe

    Functional proteins—which are long, folded chains of amino acids—cannot be assembled unless all the chiral amino acids (19 out of the 20 bioactive amino acids are chiral) either are 100 percent left-handed or 100 percent right-handed. One wrong-handed amino acid incorporated into a protein is enough to disrupt the folding configuration of the protein and, thus, block its capacity to function.

    Similarly, DNA and RNA molecules cannot be assembled unless all the ribose sugars are 100 percent left-handed or 100 percent right-handed. For example, two complementary strands of DNA cannot bind together into the life-critical double helix unless all the ribose sugars bonding the nucleobases together possess the same handedness.

    Source

    © Copyright Original Source



    Blessings,
    Lee
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

  10. #10
    tWebber lee_merrill's Avatar
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    Quote Originally Posted by shunyadragon View Post
    Source: https://scitechdaily.com/did-life-emerge-in-the-primordial-soup-via-dna-or-rna-surprising-answer-from-new-research/



    Did Life Emerge in the “Primordial Soup” via DNA or RNA? Surprising Answer From New Research
    TOPICS:BiochemistryDNAEvolutionGenetics
    By UK RESEARCH AND INNOVATION JUNE 7, 2020

    Primordial Soup Concept

    ...
    The team’s experiments to simulate early Earth geochemistry showed that four of the building blocks for DNA and RNA can arise from the same reagents and conditions.

    © Copyright Original Source

    Well, were these building blocks racemic?

    Source: Reasons to Believe

    These requirements demand that the origin of homochiral amino acids and ribose sugars must precede the origin of proteins, DNA, and RNA. That is, without preexisting large reservoirs of exclusively left-handed amino acids for each of the 19 bioactive amino acids and preexisting large reservoirs of exclusively right-handed ribose sugars, any naturalistic assembly of proteins, DNA, and RNA is ruled out. Without such reservoirs, naturalistic origin-of-life models are prohibited.

    Source

    © Copyright Original Source



    Blessings,
    Lee
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

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