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Science Forum

  1. 01 Dec '09 10:11
    From: http://news.biocompare.com/News/NewsStory/300455/NewsStory.html

    A key question in the origin of biological molecules like RNA and DNA is how they first came together billions of years ago from simple precursors. Now, in a study appearing in this week's JBC, researchers in Italy have reconstructed one of the earliest evolutionary steps yet: generating long chains of RNA from individual subunits using nothing but warm water.

    Many researchers believe that RNA was one of the first biological molecules present, before DNA and proteins; however, there has been little success in recreating the formation on RNA from simple "prebiotic" molecules that likely were present on primordial earth billions of years ago.

    Now, Ernesto Di Mauro and colleagues found that ancient molecules called cyclic nucleotides can merge together in water and form polymers over 100 nucleotides long in water ranging from 40-90 °C –similar to water temperatures on ancient Earth.

    Cyclic nucleotides like cyclic-AMP are very similar to the nucleotides that make up individual pieces of DNA or RNA (A, T, G and C), except that they form an extra chemical bond and assume a ring-shaped structure. That extra bond makes cyclic nucleotides more reactive, though, and thus they were able to join together into long chains at a decent rate (about 200 hours to reach 100 nucleotides long).

    This finding is exciting as cyclic nucleotides themselves can be easily formed from simple chemicals like formamide, thus making them plausible prebiotic compounds present during primordial times. Thus, this study may be revealing how the first bits of genetic information were created.
  2. 01 Dec '09 10:41
    Originally posted by Diodorus Siculus
    From: http://news.biocompare.com/News/NewsStory/300455/NewsStory.html

    A key question in the origin of biological molecules like RNA and DNA is how they first came together billions of years ago from simple precursors. Now, in a study appearing in this week's JBC, researchers in Italy have reconstructed one of the earliest evolutionary steps yet: ...[text shortened]... es. Thus, this study may be revealing how the first bits of genetic information were created.
    Fantastic facts! Indeed they are!

    So with the right conditions it would be impossible not to expect life to emerge!
    The Earth had the right conditions a long time ago, and - voilà - here we are!
  3. 01 Dec '09 12:09 / 3 edits
    Originally posted by FabianFnas
    Fantastic facts! Indeed they are!

    So with the right conditions it would be impossible not to expect life to emerge!
    The Earth had the right conditions a long time ago, and - voilà - here we are!
    I would, with repect, caution against the use of words like "impossible" in relation to this sort of new data leading to the emergence of life - in Costanzo et al. J Biol Chem 2009 "Generation of Long RNA chains in Water". However, I do share your enthusiasm that it is tantalising new evidence on potentially how protogenetic information may arise de novo with remarkably the simple heating of water, a chemical substance which we know now is not unique to this planet.
  4. 01 Dec '09 12:59
    Originally posted by Diodorus Siculus
    I would, with repect, caution against the use of words like "impossible" in relation to this sort of new data leading to the emergence of life - in Costanzo et al. J Biol Chem 2009 "Generation of Long RNA chains in Water". However, I do share your enthusiasm that it is tantalising new evidence on potentially how protogenetic information may arise de ...[text shortened]... imple heating of water, a chemical substance which we know now is not unique to this planet.
    Well, impossible...
    I say that the forming of a 'life molecule' would be spontaneous with the right conditions.
    And the conditions were exactly right at the beginning!
  5. Standard member sonhouse
    Fast and Curious
    01 Dec '09 15:21
    Originally posted by FabianFnas
    Well, impossible...
    I say that the forming of a 'life molecule' would be spontaneous with the right conditions.
    And the conditions were exactly right at the beginning!
    And now it seems there were cataclysm's early on that wiped out life pretty much 100%, then it came right back. So it would seem life is destined to be in any halfway civilized place in the universe!
  6. Subscriber AThousandYoung
    Do ya think?
    02 Dec '09 11:32
    Originally posted by Diodorus Siculus
    From: http://news.biocompare.com/News/NewsStory/300455/NewsStory.html

    A key question in the origin of biological molecules like RNA and DNA is how they first came together billions of years ago from simple precursors. Now, in a study appearing in this week's JBC, researchers in Italy have reconstructed one of the earliest evolutionary steps yet: ...[text shortened]... es. Thus, this study may be revealing how the first bits of genetic information were created.
    If I were more motivated I would gather together some Young Earth Creationist comments about what is "impossible" for scientists to do with respect to abiogenesis. Eventually they'll all be shown wrong, but they'll keep changing what they say if nobody records it at the time and then brings it up later when the prediction is proven false.
  7. 02 Dec '09 11:34
    Originally posted by AThousandYoung
    If I were more motivated I would gather together some Young Earth Creationist comments about what is "impossible" for scientists to do with respect to abiogenesis. Eventually they'll all be shown wrong, but they'll keep changing what they say if nobody records it at the time and then brings it up later when the prediction is proven false.
    Don't. Just don't bring them here. Don't feed the trolls.
  8. Standard member sonhouse
    Fast and Curious
    02 Dec '09 16:52
    Originally posted by AThousandYoung
    If I were more motivated I would gather together some Young Earth Creationist comments about what is "impossible" for scientists to do with respect to abiogenesis. Eventually they'll all be shown wrong, but they'll keep changing what they say if nobody records it at the time and then brings it up later when the prediction is proven false.
    Even if scientists created a viable life form in the lab that reproduced, ate food, etc., just like a real bacteria, creationists would deny, deny, deny, or call it the work of the devil.
  9. 03 Dec '09 13:06
    The missing step in a plausible scenario for the origin of living systems on this planet is the abiotic synthesis of long chains of RNA which for a number of reasons is thought to have the been the original informational polymer for genetic systems when life began.

    This paper fills this gap to a degree, however, the concentrations of the reactants was quite high I thought (>mM). This issue aside, I think the data is remarkable and what was previously considered highly unlikely on thermodynamic grounds, which is probably why nobody ever tried, has now been demonstarted to occur in the simplest conceivable solvent.

    That these cyclic nucleotides amazingly can spontaneously polymerise and without enzymatic assistance in water gives a scheme for how "self-polymerising systems" may have arisen leading to a (pre)genetic system.

    The origins of open and closed cyclic nucleotides requires "unsophisticated chemistry" they mention and this would appear to be the main issue as there would have been plenty of "warm little ponds".
  10. Subscriber AThousandYoung
    Do ya think?
    06 Dec '09 01:34
    Originally posted by Diodorus Siculus
    The missing step in a plausible scenario for the origin of living systems on this planet is the abiotic synthesis of long chains of RNA which for a number of reasons is thought to have the been the original informational polymer for genetic systems when life began.

    This paper fills this gap to a degree, however, the concentrations of the reactan ...[text shortened]... would appear to be the main issue as there would have been plenty of "warm little ponds".
    High concentrations aren't a big problem. Consider a tidal pool neat the equator. Seawater splashes into it at high tide - it's right at the edge of the tide. Then, for the rest of the day, the sun evaporates water. The next day a little more splashes in, more sunlight evaporates water, etc.
  11. 06 Dec '09 13:49
    Originally posted by AThousandYoung
    High concentrations aren't a big problem. Consider a tidal pool neat the equator. Seawater splashes into it at high tide - it's right at the edge of the tide. Then, for the rest of the day, the sun evaporates water. The next day a little more splashes in, more sunlight evaporates water, etc.
    Yes, I agree this a highly plausible scenario whereby a concentration gradient of reactants could be established. As water appears now to be far more abundant than we had previously thought elsewhere in the universe then earth is perhaps not the best place to look for abiotic synthesis of cyclic nucleotides (or for that matter other organic molecules) due to obvious contamination issues. Indeed, infrared spectroscopy of interstellar space has observed a diverse array of these chemicals like CH4, HCHO, CH3OH, HC3N. The more we learn about the ability of life to exist in highly challenging environments on earth I am quite confident that life will be identified on somewhere like Titan or Europa in the next few decades.
  12. Subscriber AThousandYoung
    Do ya think?
    07 Dec '09 01:33
    Originally posted by Diodorus Siculus
    Yes, I agree this a highly plausible scenario whereby a concentration gradient of reactants could be established. As water appears now to be far more abundant than we had previously thought elsewhere in the universe then earth is perhaps not the best place to look for abiotic synthesis of cyclic nucleotides (or for that matter other organic molecule ...[text shortened]... onfident that life will be identified on somewhere like Titan or Europa in the next few decades.
    I suspect life is more common than I previously thought as well.

    I mean...it's a logical chemical progression!
  13. 07 Dec '09 13:21
    Originally posted by AThousandYoung
    I suspect life is more common than I previously thought as well.

    I mean...it's a logical chemical progression!
    Below is a recent abstract, I think may be of interest:

    Astrobiology. 2009 May;9(4):335-43.

    The search for alien life in our solar system: strategies and priorities.

    Shapiro R, Schulze-Makuch D.

    Department of Chemistry, New York University , New York, New York 10003, USA.

    With the assumption that future attempts to explore our Solar System for life will be limited by economic constraints, we have formulated a series of principles to guide future searches: (1) the discovery of life that has originated independently of our own would have greater significance than evidence for panspermia; (2) an unambiguous identification of living beings (or the fully preserved, intact remains of such beings) is more desirable than the discovery of markers or fossils that would inform us of the presence of life but not its composition; (3) we should initially seek carbon-based life that employs a set of monomers and polymers substantially different than our own, which would effectively balance the need for ease of detection with that of establishing a separate origin; (4) a "follow-the-carbon" strategy appears optimal for locating such alternative carbon-based life. In following this agenda, we judge that an intensive investigation of a small number of bodies in our Solar System is more likely to succeed than a broad-based survey of a great number of worlds. Our priority for investigation is (1) Titan, (2) Mars, (3) Europa. Titan displays a rich organic chemistry and offers several alternative possibilities for the discovery of extant life or the early stages that lead to life. Mars has already been subjected to considerable study through landers and orbiters. Although only small amounts of methane testify to the inventory of reduced carbon on the planet, a number of other indicators suggest that the presence of microbial life is a possibility. Care will be needed, of course, to distinguish indigenous life from that which may have spread by panspermia. Europa appears to contain a subsurface ocean with the possibility of hydrothermal vents as an energy source. Its inventory of organic carbon is not yet known.
  14. 08 Dec '09 03:24 / 1 edit
    Originally posted by Diodorus Siculus
    The missing step in a plausible scenario for the origin of living systems on this planet is the abiotic synthesis of long chains of RNA which for a number of reasons is thought to have the been the original informational polymer for genetic systems when life began.

    This paper fills this gap to a degree, however, the concentrations of the reactan would appear to be the main issue as there would have been plenty of "warm little ponds".
    The concentrations are raised in fatty acid vesicles... The video's a little slow but explains it rather well from about 3.50
    http://www.youtube.com/watch?v=U6QYDdgP9eg&annotation_id=annotation_446810&feature=iv
  15. Subscriber AThousandYoung
    Do ya think?
    08 Dec '09 04:37
    Originally posted by mrstabby
    The concentrations are raised in fatty acid vesicles... The video's a little slow but explains it rather well from about 3.50
    http://www.youtube.com/watch?v=U6QYDdgP9eg&annotation_id=annotation_446810&feature=iv
    Yeah, that too...the small monomers can slip in, but then they get polymerized and cannot get out.