The undreamt-of breakthrough of molecular biology has made the problem of the origin of life a greater riddle than it was before: we have acquired new and deeper problems. — Karl R. Popper, 1974 (0)
The RNA World
Virtually all biologists now agree that bacterial cells cannot form from nonliving chemicals in one step. If life arises from nonliving chemicals, there must be intermediate forms, "precellular life." Of the various theories of precellular life, the leading contender is the RNA world.
There is a lot to learn about RNA, and research like this is how we learn it. But these and other similar findings, arrived at in highly orchestrated experiments that start with biologically produced RNA, are very far from proving that the RNA world is the pathway between nonlife and life. In nature, far from the sterilized laboratory, uncontaminated RNA strands of any size would be unlikely to form in the first place. "... The direct synthesis of ... nucleotides from prebiotic precursors in reasonable yield and unaccompanied by larger amounts of unrelated molecules could not be achieved by presently known chemical reactions" (5).
At the Salk Institute for Biological Studies, in 1994, Leslie Orgel observes, "Because synthesizing nucleotides and achieving replication of RNA under plausible prebiotic conditions have proved so challenging, chemists are increasingly considering the possibility that RNA was not the first self replicating molecule..." (9).
Apparently NASA has lost enthusiasm for the RNA world as well. In the Final Report issued after the "Astrobiology Workshop" held September 9-11, 1996 at Ames Research Center, California, we read (10),
It has been postulated that there was a time in protobiological evolution when RNA played a dual role as both genetic material and a catalytic molecule ("the RNA world"). However, this appealing concept encounters significant difficulties. RNA is chemically fragile and difficult to synthesize abiotically. The known range of its catalytic activities is rather narrow, and the origin of an RNA synthetic apparatus is unclear.
In spite of the intense level of work on the RNA world in the last decade, there is no consensus theory for precellular life. There are many theories. Here are some of the others —
To go from a bacterium to people is less of a step than to go from a mixture of amino acids to a bacterium. — Lynn Margulis (21.5)
The only premise that all of the precellular theories share is that it would be an extremely long time before the first bacterial cells evolved. If precellular life somehow got going, it could then conceivably begin to crank out, by some precellular process, random strings of nucleotides and amino acids, trying to luck into a gene or a protein with advantages which would lead to bacterial life. There is no evidence in life today of anything that produces huge quantities of new, random strings of nucleotides or amino acids, some of which are advantageous. But if precellular life did that, it would need lots of time to create any useful genes or proteins. How long would it need? After making some helpful assumptions we can get the ratio of actual, useful proteins to all possible random proteins up to something like one in 10^500 (ten to the 500th power). So it would take, barring incredible luck, something like 10^500 trials to probably find one. Imagine that every cubic quarter-inch of ocean in the world contains ten billion precellular ribosomes. Imagine that each ribosome produces proteins at ten trials per minute (about the speed that a working ribosome in a bacterial cell manufactures proteins). Even then, it would take about 10^450 years to probably make one useful protein. But Earth was formed only about 4.6 x 10^9 years ago. The amount of time available for this hypothetical protein creation process was maybe a few hundred million or ~10^8 years. And now, to make a cell, we need not just one protein, but a minimum of several hundred.
So even if we allow precellular life, there is a problem getting from there to proteins, genes and cells. The random production of proteins does not succeed as an explanation. Other intermediate, unspecified stages must be imagined. We could call these stages post-precellular life. By whatever means, life's evolution through these stages would have to be time-consuming.
One advocate of the RNA world, Gerald Joyce, allows 400 million years for "The Rise and Fall of the RNA World" (22):
...At some point RNA organisms began to dabble in the use of short peptides, leading eventually to the development of protein synthesis. Other "experiments" led to the discovery of DNA, which provided a more stable repository for genetic information. By 3.6 to 3.8 billion years ago all of these events had come to pass; the RNA world had fallen and the DNA/protein world had risen in its place.
But other researchers see evidence for prokaryotic cells in the first 100 million years, maybe even immediately. "...Actual cells have been found in the earth's oldest unmetamorphosed sediments...," says Gould in Wonderful Life (23). Bada says that cyanobacteria may have emerged only ten million years after the first precellular life (24). In November, 1996, S. J. Mojzsis of the Scripps institution of Oceanography and others reported isotopic evidence that cellular metabolism was under way before 3.8 billion years ago (25). Even before the research by Mojzsis et al., Francis Crick was worried by the time problem. "...The real fossil record suggests that our present form of protein based life was already in existence 3.6 billion years ago.... This leaves an astonishingly short time to get life started" (26). Another researcher, Yale biochemist Peter B. Moore, says this about the time problem (27):
Of one thing we can be certain: The RNA world—if it ever existed—was short-lived. The earth came into existence about 4.5 x 10^9 years ago, and fossil evidence suggests that cellular organisms resembling modern bacteria existed by 3.6 x 10^9 years before the present.... There are even hints that those early organisms engaged in photosynthesis, which is likely to have been a protein-dependent process then, as now. Thus it appears likely that organisms with sophisticated, protein based metabolisms existed only 0.9 x 10^9 years after the planet's birth.
The "window of opportunity" for the RNA world was much shorter than 0.9 x 10^9 years. The earth's surface was uninhabitable at the beginning due to heat generated by meteoric bombardment and its geological differentiation. ...Thus, the interval in which the biosphere could have been dominated by RNA-based life forms may be less than 100 million years. Incidentally, when one starts thinking along these lines, one must consider the unthinkable, i.e., that the length of time that RNA-based proteins actually bestrode the earth might be zero.
We said that research in the RNA world is a medium-sized industry. This research has demonstrated how exceedingly difficult it would be for living cells to originate by chance from nonliving matter in the time available on Earth. That demonstration is a valuable contribution to science. Additional research will be valuable as well. But to keep insisting that life can spontaneously emerge from nonliving chemicals in the face of the newly comprehended difficulties is puzzling. It is reminiscent of the persistent efforts of medieval alchemists to turn lead into gold.
There is another scientific explanation for the origin of life on Earth. It is that whole cells arrived here from space. (Life "in the first place" is a separate issue, dealt with elsewhere on this website.)
|The Origin of Handheld Calculators: A spoof on origin-of-life theories in terms of the computer analogy (see A Cell is Like a Computer): |
The fossil record indicates that there were handheld calculators with at least 240 kilobytes of stored programs in existence almost as soon as the earth cooled. Possibly, handheld calculators originated when special conditions allowed the formation of silicon chips and circuit boards (primitive genes). Heat, perhaps generated by radioactivity, volcanoes or meteor impacts, melted some sand to form a silicon flake. Random splashing of molten metal caused metal filaments to form a circuit board on the flake. Oily film on ponds dried into the hard plastic material needed for the shell.
Lightning provided the first source of electrical power. Prototypes in seawater, at just the right distance from the strike, received sufficient voltage without being destroyed. Batteries (allowing independent metabolism) came later. The first batteries were iron acid batteries, formed in mud pockets. Lithium batteries were a very late development.
This primitive protocalculator somehow acquired ten to 25 bytes of stored programs (40 to 100 nucleotides) that enabled it to have some function that made it useful. Now we find evidence for only the fully evolved handheld calculators similar to the ones used today, with function keys and lengthy installed programs, because the fossil record is incomplete.
Remnants of an Ancient Metabolism without Phosphate, by Joshua E. Goldford et al., doi:10.1016/j.cell.2017.02.001, Cell, 02 Mar 2017.
26 Feb 2017: ...the common ancestor ...did encode many of the protein domains of all three super-kingdoms.
email to Ted Steele on the origin of life, 17 Feb 2017.
Synchronized chaotic targeting and acceleration of surface chemistry in prebiotic hydrothermal microenvironments, by Aashish Priye et al., doi:10.1073/pnas.1612924114, PNAS, 07 Feb 2017. Our results suggest that chaotic thermal convection may play a previously unappreciated role in mediating surface-catalyzed synthesis in the prebiotic milieu.
Crystal structure of Pistol, a class of self-cleaving ribozyme, by Laura A. Nguyen et al., doi:10.1073/pnas.1611191114, PNAS, 31 Jan 2017.
06 Jan 2017: Either life developed here super-fast or it came full-on as DNA life from afar — Gary Ruvkun, SETG.
09 Dec 2016: The History and Philosophy of Origin Research (Tokyo conference report).
Meteorites and the RNA World: A Thermodynamic Model of Nucleobase Synthesis within Planetesimals, by Ben K. D. Pearce and Ralph E. Pudritz, Astrobiology, online 09 Nov 2016.
01 Nov 2016: ...Then, perhaps within minutes, the first cell came into existence.
A viscous solvent enables information transfer from gene-length nucleic acids in a model prebiotic replication cycle, by Christine He et al., doi:10.1038/nchem.2628, Nature Chemistry, online 10 Oct 2016. ...suggesting that viscosity-mediated replication is possible for a range of genetic polymers, perhaps even for informational polymers that may have preceded RNA.
Autocatalytic, bistable, oscillatory networks of biologically relevant organic reactions, by Sergey N. Semenov et al., doi:10.1038/nature19776, Nature, 29 Sep 2016. By using small organic molecules to build a network of organic reactions with autocatalytic, bistable and oscillatory behaviour, we identify principles that explain the ways in which dynamic networks relevant to life could have developed.
...RNA World Deep Beneath the Surface, by Mary L. Martialay, Rensselaer Polytechnic Institute (+Newswise), 06 Sep 2016.
Amplification of RNA by an RNA polymerase ribozyme by David P. Horning and Gerald F. Joyce, doi:10.1073/pnas.1610103113, PNAS, online 15 Aug 2016; and commentary: TSRI Scientists Take Big Step Toward Recreating Primordial 'RNA World' of Four Billion Years Ago, The Scripps Research Institute, 15 Aug 2016.
Life may have emerged not once, but many times on Earth by Penny Sarchet, New Scientist, 17 Aug 2016.
The physiology and habitat of the last universal common ancestor by Madeline C. Weiss, Filipa L. Sousa et al., doi:10.1038/nmicrobiol.2016.116, Nature Microbiology, 25 Jul 2016.
A violent sun and a sky full of laughing gas could have led to life on Earth, by Sarah Kaplan, Washington Post, 23 May 2016.
Life's origins may result from low-energy electron reactions in space, PhysOrg.com, 13 Jun 2016. ...Low-energy, electron-induced condensed phase reactions may contribute to the interstellar synthesis of prebiotic molecules previously thought to form exclusively via UV photons....
Beyond prebiotic chemistry by Leroy Cronin and Sara Imari Walker, doi:10.1126/science.aaf6310, Science, 03 Jun 2016. Progress in understanding the origin of life may come from studying how simple chemical networks can transform into living networks.
Making RNA in the prebiotic world by Sidney Becker, Ines Thoma et al., doi:10.1126/science.aad28, Science, 13 May 2016. This nucleoside formation pathway can be fused to sugar-forming reactions to produce pentosides, providing a plausible scenario of how purine nucleosides may have formed under prebiotic conditions. Commentary: Building blocks for 'RNA world' made from simple ingredients by Davide Castelvecchi, Nature, 12 May 2016.
Comet Craters - Literal Melting Pots for Life on Earth, Trinity College Dublin (+Newswise), 04 May 2016.
Missing Links Brewed in Primordial Puddles?, Georgia Institute of Technology (+Newswise), 25 Apr 2016. Using two molecules known as barbituric acid and melamine, the researchers formed proto-nucleotides so strongly resembling two of RNA's nucleotides that it is tempting to speculate that they are indeed their ancestors.
Dynamics of prebiotic RNA reproduction illuminated by chemical game theory by Jessica A. M. Yeates et al., doi:10.1073/pnas.1525273113, PNAS, online 18 Apr 2016. ...Three RNA genotypes can stably coexist in a rock-paper-scissors analog.
Ribose and related sugars from ultraviolet irradiation of interstellar ice analogs by Cornelia Meinert et al., doi:10.1126/science.aad8137, v352 Science, 08 Apr 2016.
12 Mar 2016: I don't think anybody feels any more confident about how life got going in the first place than they did 30 years ago. — Sir Patrick Bateson
A Strategy for Origins of Life Research, by Caleb Scharf et al., doi:10.1089/ast.2015.1113, Astrobiology, 12 Nov 2015.
20 Oct 2015: Carbon isotopes that may point to life have been found in 4.1 billion-year-old zircon.
Alexei V. Tkachenko and Sergei Maslov, "Spontaneous emergence of autocatalytic information-coding polymers" [article], doi:10.1063/1.4922545, n 045102 v 143, The Journal of Chemical Physics, 2015; and commentary: "New Computer Model Could Explain how Simple Molecules Took First Step Toward Life," Newswise, 28 Jul 2015.
Cleaves H. James II, Meringer Markus, and Goodwin Jay, "227 Views of RNA: Is RNA Unique in Its Chemical Isomer Space?" [abstract], doi:10.1089/ast.2014.1213, Astrobiology, 7 Jul 2015.
Jay G. Forsythe et al., "Ester-Mediated Amide Bond Formation Driven by Wet- Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth" [abstract], doi:10.1002/anie.201503792, Angewandte Chemie, 15 Jul 2015; and commentary:
Did a puddle in flux spark life on Earth?, Georgia Institute of Technology (+Newswise), 20 Jul 2015.
John A. Baross and William F. Martin, "The Ribofilm as a Concept for Life's Origins" [abstract], doi:10.1016/j.cell.2015.06.038, p 13-15 v 162, Cell, 2 Jul 2015.
Why 'RNA world' theory on origin of life may be wrong after all by Bob Holmes, New Scientist, 24 Jun 2015.
23 Jun 2015: The Origin of Life Circus, by Suzan Mazur.
Scientists find new evidence of key ingredient during dawn of life, University of North Carolina (+SpaceDaily), 18 Jun 2015; and earlier: New evidence emerges on the origins of life on Earth, University of North Carolina (+Newswise), 1 Jun 2015."Their findings... fly in the face of the problematic 'RNA world' theory...."
Wim Hordijk, "The Living Set", The Scientist, 1 Jun 2015. "Mathematical and computational approaches are making strides in understanding how life might have emerged and organized itself from the basic chemistry of early Earth."
Martin Ferus et al., "Meteorite-catalyzed synthesis of nucleosides and other prebiotic compounds" [abstract], doi:10.1073/pnas.1507471112, Proc. Natl. Acad. Sci. USA, online 28 May 2015.
Life's Elusive X-Factor?... by Suzan Mazur, Huffington Post, 22 May 2015. "...Nothing much has happened since Miller-Urey yet scientists keep pursuing the same lines of investigation," says biochemist Pier Luigi Luisi.
Remembering Origin of Life Trailblazer Harry Lonsdale by Suzan Mazur, Huffington Post, 5 Jan 2015. He died 11 Nov 2014.
Dorian S. N. Parker et al., "Gas Phase Synthesis of (Iso)Quinoline and its Role in the Formation of Nucleobases in the Interstellar Medium" [abstract], doi:10.1088/0004-637X/803/2/53, The Astrophysical Journal, 1 May 2015; and commentary: A Hot Start to the Origin of Life? by Kate Greene, Berkeley Lab (+PhysOrg.com), 5 May 2015.
A. Roldan et al., "Bio-inspired CO2 conversion by iron sulfide catalysts under sustainable conditions" [Open Access abstract], doi:10.1039/C5CC02078F, Chem. Commun., online 24 Mar 2015; and commentary: Hydrothermal Vents Able to Create Simple Organic Molecules, Sci-News.com, 29 Apr 2015.
Christian Mayer, Ulrich Schreiber and María J. Dávila, "Periodic Vesicle Formation in Tectonic Fault Zones—an Ideal Scenario for Molecular Evolution" [abstract], doi:10.1007/s11084-015-9411-z, Origins of Life and Evolution of Biospheres, online 27 Feb 2015. By email, Ulrich writes, "We can show the development of vesicles, peptides (and next nucleotides) under conditions of the upper continental crust (open systems in tectonic fault zones) in super critical CO2. We detected the first organic chemistry in quartz minerals of tectonic fault zones in Archean quartz dykes of Western Australia."
25 Mar 2015: Origin-of-life puzzle cracked
How Earth's earliest life overcame a genetic paradox by Tim Wogan, Science News, 30 Jan 2015. "Longer RNA chains could have hidden out in porous rocks near volcanic sites such as hydrothermal ocean vents, where unique temperature conditions might have helped complex organisms evolve."
Meredith Root-Bernstein and Robert Root-Bernstein, "The ribosome as a missing link in the evolution of life" [html], doi:10.1016/j.jtbi.2014.11.025, p 130-158 v 367, Journal of Theoretical Biology, 21 Feb 2015. "Cells – and DNA itself – evolved, we argue, to optimise the functioning of ribosomes;" and commentary: Never mind the selfish gene - ribosomes are the missing link, The Conversation (+PhysOrg.com), 7 Jan 2015.
Martin Ferus et al., "High-energy chemistry of formamide: A unified mechanism of nucleobase formation" [abstract], doi:10.1073/pnas.1412072111, Proc. Natl. Acad. Sci. USA, online 8 Dec 2014.
Jonathan T. Sczepanski and Gerald F. Joyce, "A cross-chiral RNA polymerase ribozyme" [html], doi:10.1038/nature13900, p 440-442 v 515, Nature, 20 Nov (online 29 Oct) 2014; and commentary: ...Scientists Make Enzyme that Could Help Explain Origins of Life, Scripps Research Institute (+PhysOrg.com +Newswise), 29 Oct 2014.
David Deamer, "Origin of life: The first spark" (review of In Search of Cell History by Franklin M. Harold, University of Chicago Press: 2014) [html], doi:10.1038/514302a, p 302-303 v 514, Nature, 15 Oct 2014.
J.M. Dreiling and T.J. Gay, "Chirally Sensitive Electron-Induced Molecular Breakup and the Vester-Ulbricht Hypothesis" [abstract], doi:10.1103/PhysRevLett.113.118103, n 118103 v 113, Phys. Rev. Lett., 12 Sep 2014; and commentary: Force of nature gave life its asymmetry by Elizabeth Gibney, doi:10.1038/nature.2014.15995, Nature News, 25 Sep 2014.
Zerulla K, Chimileski S, Näther D, Gophna U, Papke RT, et al., "DNA as a Phosphate Storage Polymer and the Alternative Advantages of Polyploidy for Growth or Survival" [html], doi:10.1371/journal.pone.0094819, 9(4): e94819, PLoS ONE, 14 Apr 2014; and commentary: DNA may have had humble beginnings as nutrient carrier by Adam Hadhazy, PhysOrg.com, 1 Sep 2014. "DNA might have initially evolved for the purpose of storing phosphate...."
Origin of Life Project: Second Annual Reports, Jul 2014.
Stanley Miller's Forgotten Experiments, Analyzed, Georgia Tech (+Newswise), 25 Jun 2014.
A New Physics Theory of Life, re: Jeremy England, by Natalie Wolchover, Quanta Magazine, 22 Jan 2014. "...The underlying principle driving the whole process is dissipation-driven adaptation of matter."
William F. Martin, Filipa L. Sousa and Nick Lane, "Energy at life's origin" [abstract], doi:10.1126/science.1251653, p 1092-1093 v 344, Science, 6 Jun 2014. "...Suggesting that natural ion gradients in [hydrothermal] vents ignited life's ongoing chemical reaction."
Markus A Keller, Alexandra V Turchyn and Markus Ralser, "Non-enzymatic glycolysis and pentose phosphate pathway-like reactions in a plausible Archean ocean" [html], doi:10.1002/msb.20145228, 725 v10, Mol. Syst. Biol., 1 Apr 2014. "These results ...support the hypothesis that the topology of extant metabolic network could have originated from the structure of a primitive, metabolism-like, prebiotic chemical interconversion network"; and commentary: Pier Luigi Luisi, "Prebiotic metabolic networks?" [html], doi:10.1002/msb.20145351, 729 v10, Mol. Syst. Biol., 1 Apr 2014.
Tom Froese, Nathaniel Virgo and Takashi Ikegami, "Motility at the Origin of Life: Its Characterization and a Model" [abstract | full text], doi:10.1162/ARTL_a_00096, p 55-76 v 1, Artificial Life, Winter 2014. "...We conclude by speculating about the feasibility of a movement-first approach to the origin of life."
Jef Akst, "RNA World 2.0" [html], The Scientist, 1 Mar 2014.
Jimmy Gollihar, Matthew Levy and Andrew D. Ellington, "Many Paths to the Origin of Life" [summary], doi:10.1126/science.1246704, p 259-260 v 343, Science, 17 Jan 2014.
20 Dec 2013: Eugene V. Koonin's book, The Logic of Chance
Katarzyna Adamala and Jack W. Szostak, "Nonenzymatic Template-Directed RNA Synthesis Inside Model Protocells" [abstract], doi:10.1126/science.1241888, p 1098-1100 v 342, Science, 29 Nov 2013; and commentary: Robert F. Service, "The Life Force" [intro], doi:10.1126/science.342.6162.1032, p 1032-1034 v 342, Science, 29 Nov 2013. "'Laboratories will be creating a living cell within ten years,' Colin Pittendrigh, an American biologist, predicted in 1967."
Ancient Minerals: Which Gave Rise to Life?, Carnegie Institution for Science (+PhysOrg.com), 25 Nov 2013.
...Further evidence of 'RNA world' origin in modern life, The University of Chicago Medicine (+PhysOrg.com), 6 Nov 2013.
Clay May Have Been Birthplace of Life On Earth..., ScienceDaily (+Newswise.com), 5 Nov 2013.
Paleontologist Presents Origin of Life Theory, Texas Tech University (+PhysOrg.com +Newswise.com), 29 Oct 2013. "This is what we've all searched for - the Holy Grail of science."
18 Oct 2013: Manfred Eigen's new book, From Strange Simplicity to Complex Familiarity.
Li Li, Christopher Francklyn and Charles W. Carter Jr., "Aminoacylating Urzymes Challenge the RNA World Hypothesis" [abstract | editor's comment], doi:10.1074/jbc.M113.49612, p 26856-26863 v 288, The Journal of Biological Chemistry, 13 Sep 2013; and more commentary: New findings challenge assumptions about origins of life, UNC School of Medicine (+PhysOrg.com +Newswise), 13 Sep 2013. "The RNA world hypothesis is extremely unlikely. It would take forever."
13 Sep 2013: A major problem with all origin-of-life theories — how did biological "self-preservation" arise?
First Annual Review of Research by the 2011 Winners of the "Origin of Life Challenge", Jul 2013.
30 Aug 2013: Life on Earth may have come from Mars, acording to Steve Benner.
Roy A. Black et al., "Nucleobases bind to and stabilize aggregates of a prebiotic amphiphile, providing a viable mechanism for the emergence of protocells" [abstract], doi:10.1073/pnas.1300963110, Proc. Natl. Acad. Sci. USA, 30 Jul 2013; and commentary: Natural affinities – unrecognized until now – may have set stage for life to ignite by Sandra Hines, Universty of Washington, 29 Jul 2013.
Michael J. Russell et al., "The inevitable journey to being" [abstract], doi:10.1098/rstb.2012.0254, n1622 v368, Phil. Trans. R. Soc. B, 19 Jul 2013; and commentary: Cracking how life arose on Earth may help clarify where else it might exist, PhysOrg.com, 30 Jul 2013.
Karl Friston, "Life as we know it" [abstract], doi:10.1098/rsif.2013.0475, n86 v10, J. R. Soc. Interface, 6 Sep (online 3 Jul) 2013. "This paper presents a heuristic proof (and simulations of a primordial soup) suggesting that life—or biological self-organization—is an inevitable and emergent property of any (ergodic) random dynamical system that possesses a Markov blanket."
Prebiotic Chemistry: Focus Issue [index with Open Acess links], n5 v5, Nature Chemistry, online 19 May 2013.
18 Apr 2013: Earth was seeded by panspermia. (Points to an article with a new theory, "Coenzynme World".)
David E. Bryant et al., "Hydrothermal modification of the Sikhote-Alin iron meteorite under low pH geothermal environments. A plausibly prebiotic route to activated phosphorus on the early Earth" [html], p 90-112 v109, Geochimica et Cosmochimica Acta, 15 May 2013; and commentary: Unusual Extraterrestrial Phosphorus Triggered Origin Of Life - A Key Puzzle May Be Solved!, MessageToEagle.com, 4 Apr 2013.
Liam M. Longo et al., "Simplified protein design biased for prebiotic amino acids yields a foldable, halophilic protein" [abstract], doi:10.1073/pnas.1219530110, p2135-2139 v110, Proc. Natl. Acad. Sci. USA, 5 Feb 2013; and commentary: Origins of life? ...New Clues by Doug Carlson, Florida State University (+Newswise), 5 Apr 2013.
Origin of Life Souffle Rises by Susan Mazur, TheHuffingtonPost.com, 13 Mar 2013.
Christian de Duve, "The Other Revolution in the Life Sciences" [abstract], doi:10.1126/science.339.6124.1148-a, p1148 v339, Science, 8 Mar 2013. Before Gilbert's widely publicized "RNA world", there may have been Baltcheffsky's "pyrophosphate world", Wächtershäuser's "iron-sulfur world", or my "thioester world".
How did early primordial cells evolve?, PhysOrg.com, 28 Feb 2013. "L-form bacteria become irregularly shaped and form cell surface bulges that pinch off to become daughter cells...."
Molecules Assemble in Water, Hint at Origins of Life, Georgia Institute of Technology, 20 Feb 2013.
Origin of life emerged from cell membrane bioenergetics, University College London (+ScienceDaily), 20 Dec 2012.
16 Dec 2012: Two new origin-of-life research programs are proposed.
Nilesh Vaidya et al., "Spontaneous network formation among cooperative RNA replicators" [abstract], doi:10.1038/nature11549, p72-77 — and commentary by James Attwater and Philipp Holliger, "Origins of life: The cooperative gene" [abstract], p48-49 — v491, Nature, 1 Nov 2012.
Early-Earth Cells Modeled to Show How First Life Forms Might Have Packaged RNA, Penn State University (also EurekAlert! and PhysOrg.com), 14 Oct 2012.
The Origin of Life Challenge: Searching for How Life Began by Nola Taylor Redd, Astrobiology Magazine, 20 Jun 2012.
7 Jun 2012: An interview with Gerald Joyce is available on the Internet.
10 May 2012: The definition of life and speculations about its origin(s)... by Gerald Joyce of the Scripps Research Institute.
Vitor B. Pinheiro et al., "Synthetic Genetic Polymers Capable of Heredity and Evolution" [abstract], doi:10.1126/science.1217622, p341-344 v336, Science, 20 Apr 2012; and commentary: Molecular alternatives to DNA, RNA offer new insight into life's origins, by Richard Harth, Arizona State University (+PhysOrg.com), 19 Apr 2012. "This pre-RNA world hypothesis has been gaining ground, largely through investigations into XNAs...."
Ulrich Schreiber et al., "Hypothesis: Origin of Life in Deep-Reaching Tectonic Faults" [abstract], doi:10.1007/s11084-012-9267-4, Origins of Life and Evolution of Biospheres, online 29 Feb 2012. "...We suggest that supercritical CO2 as a nonpolar solvent could have played an important role."
31 Mar 2012: Is there life elsewhere? How did life start…?
13 Mar 2012: The standard RNA World theory is disputed following a new phylogenetic analysis.
23 Feb 2012: Armen Y. Mulkidjanian replies with comments after we linked to his article, next below:
Armen Y. Mulkidjanian et al., "Origin of first cells at terrestrial, anoxic geothermal fields" [abstract], doi:10.1073/pnas.111777410, p17425-17430 v106, Proc. Natl. Acad. Sci. USA, 21 Feb 2012. And commentaries (3):
Did Life's First Cells Evolve in Geothermal Pools? by David Biello, Scientific American, 15 Feb 2012.
Debate bubbles over the origin of life, doi:10.1038/nature.2012.10024, by Brian Switek, Nature News, 13 Feb 2012.
Russian hot springs point to rocky origins for life by Colin Barras, NewScientist, 13 Feb 2012.
The search for life's stirrings by Alvin Powell, Harvard University Gazette, 6 Feb 2012. "Nobel Prize winner Jack Szostak's research focuses on understanding primitive cells, how they might have been created, and how they might have behaved and divided."
Laurence Burroughs et al., "Asymmetric organocatalytic formation of protected and unprotected tetroses under potentially prebiotic conditions" [abstract], doi:10.1039/C1OB06798B, Organic & Biomolecular Chemistry, online 16 Nov 2011. "...Using simple left-handed amino acids to catalyse the formation of sugars resulted in the production of predominately right-handed form of sugars."
Claudia Huber, "Elements of Metabolic Evolution" [abstract], doi:10.1002/chem.201102914, Chemistry - A European Journal, online 13 Jan 2012.
A birthplace for primitive life on Earth?, Centre national de la recherche scientifique (CNRS) (+Physorg.com), 18 Oct 2011. "The mud volcanoes at Isua thus represent a particularly favorable setting for the emergence of primitive terrestrial life."
David M. J. Lilley and John D. Sutherland, eds., "The chemical origins of life and its early evolution," Discussion Meeting Issue with 17 articles [table of contents], v366 n1580, Phil. Trans. R. Soc. B, 27 Oct 2011.
Martin D. Brasier et al., "Pumice as a Remarkable Substrate for the Origin of Life" [abstract], doi:10.1089/ast.2010.0546, p725-735 v11 n7, Astrobiology, Sep 2011.
Volcanic rock rafts 'could have been cradles of life' by Mark Kinver, BBC News, 2 Sep 2011.
First life may have arisen above serpentine rock... by Max McClure, Stanford University News, 22 Sep 2011.
Massimo Di Giulio, "Biological evidence against the panspermia theory" [abstract | early version PDF], doi:10.1016/j.jtbi.2010.07.017, p569-572 v266, Journal of Theoretical Biology, 21 Oct 2010. "The tRNA split genes of Nanoarchaeum equitans and the Met-tRNAfMet->fMet-tRNAfMet pathway are independent, plesiomorphic and domain-specific traits which define a progenotic stage for the LUCA and for the ancestors of Archaea and Bacteria."
Thomas R. Cech, "The RNA Worlds in Context" [abstract], doi:10.1101/cshperspect.a006742, Perspectives in Biology, Cold Spring Harbor, online 16 Feb 2011. There are two RNA worlds.
First life: The search for the first replicator by Michael Marshall, n2585, New Scientist, 15 Aug 2011.
Jason E. Hein et al., "A route to enantiopure RNA precursors from nearly racemic starting materials" [abstract], doi:10.1038/nchem.1108, Nature Chemistry, online 7 Aug 2011.
Robert Shapiro, "Astrobiology: Life's beginnings" — review of First Life by David Deamer [html], doi:10.1038/476030a, p30-31 v476, Nature, 4 Aug 2011.
David Deamer, First Life: Discovering the Connections between Stars, Cells, and How Life Began [publisher's promo], ISBN:9780520258327, Jun 2011.
Benedikt Obermayer et al., "Emergence of Information Transmission in a Prebiotic RNA Reactor" [abstract], doi:10.1103/PhysRevLett.107.018101, v107 n018101, Physical Review Letters, online 27 Jun 2011; and commentary:
RNA reactor could have served as a precursor of life by Lisa Zyga, PhysOrg.com, 11 Jul 2011.
4 Jul 2011: A chemist has announced an Origin-Of-Life prize of 50,000 dollars.
26 May 2011: The common ancestor of life on Earth had more functional protein domains than the first cells!
24 Mar 2011: Residue from one of Stanley Miller's experiments of 1958 has been analyzed....
Meteorite cargo could solve origin-of-life riddle by Andy Coghlan, NewScientist.com, 01 Mar 2011.
Pssst! Don't tell the creationists, but scientists don't have a clue how life began by John Horgan, ScientificAmerican.com, 28 Feb 2011.
Andrei S Rodin, Eörs Szathmáry and Sergei N Rodin, "On origin of genetic code and tRNA before translation" [abstract], doi:10.1186/1745-6150-6-14, v6 n14, Biology Direct, 22 Feb 2011.
22 Feb 2011: We'll create panspermia.... — J. Craig Venter at a panel discussion of the origin of life.
Clay-Armored Bubbles ...Could Have Played a Key Role in the Origins of Life, ScienceDaily, 7 Feb 2011.
Can a Simple Model Explain the Advent of Cells? by Tim Wogan, ScienceNow, 7 Jan 2011.
Michael Yarus, Life from an RNA World: The Ancestor Within, Harvard University Press [publisher's promo], 15 Apr 2010. There was a pre-RNA world whose inhabitants actually invented replication (p 54). And a review:
Irene A. Chen, "...An RNA Whirl" (review of Life from an RNA World: The Ancestor Within, by Michael Yarus), [summary], doi:10.1126/science.1197794, p758 v330, Science, 5 Nov 2010.
2 Nov 2010: The software problem for the origin of life is not ignored, for once....
Jason P. Schrum, Ting F. Zhu and Jack W. Szostak, "The Origins of Cellular Life" [abstract], doi:10.1101/cshperspect.a002212, Cold Spring Harb. Perspect. Biol., Sep 2010.
Harold J. Morowitz et al., "Ligand Field Theory and the Origin of Life as an Emergent Feature of the Periodic Table of Elements" [abstract], p1-6 v219, The Biological Bulletin, Aug 2010; and commentary -- Transition metal catalysts could be key to origin of life... by Carol Schachinger, EurekAlert.org, 3 Sep 2010.
Could thermodynamic fluctuations have led to the origins of life? by Lisa Zyga, Physorg.com, 16 Aug 2010.
22 Jun 2010: ...Many steps in all origin-of-life scenarios remain obscure.... — Christopher F. Chyba
New Theory for Life's First Energy Source by Zoë Macintosh, LiveScience, 12 Jun 2010.
...Ultraviolet Light Helps Form "Missing G" of RNA Building Blocks by Abby Vogel Robinson, Georgia Institute of Technology (+Newswise), 14 Jun 2010.
20 May 2010: A conversation with Jeffrey L. Bada is available online.
Tu Lee and Yu Kun Lin, "The Origin of Life and the Crystallization of Aspartic Acid in Water" [abstract], doi:10.1021/cg901219f, p1652-1660 v10, Crystal Growth & Design, 27 Feb 2010.
Katharine Sanderson, "Comet crash creates potential for life" [html], doi:10.1038/news.2010.152, NatureNews, online 26 Mar 2010.
20 Mar 2010: Molecular Midwives?
Shooting Meteorites in a Barrel by Jeremy Hsu, PhysOrg.com, 26 Feb 2010. "High-impact lab experiments simulate whether the building blocks of life could have survived the rough arrival on Earth via meteorite impact."
Rebecca M. Turk et al., "Multiple translational products from a five-nucleotide ribozyme" [abstract], doi:10.1073/pnas.0912895107, Proc. Natl. Acad. Sci. USA, online 22 Feb 2010. Also see commentary — CU Team Discovers Tiny RNA Molecule With Big Implications for the Origin of Life, The University of Colorado at Boulder, 22 Feb 2010.
New research rejects 80-year theory of 'primordial soup' as the origin of life, PhysOrg.com, 2 Feb 2010.
Prussian blue linked to the origin of life, EurekAlert, 14 Dec 2009. "...When Prussian blue is dissolved in ammoniac solutions it produces hydrogen cyanide, a substance that could have played a fundamental role in the creation of the first bio-organic molecules...."
28 Nov 2009: There is no such a thing as a 'simple' bacterium — Howard Ochman and Rahul Raghavan.
Charles Darwin really did have advanced ideas about the origin of life, EurekAlert, 27 Oct 2009.
Hisashi Ohtsuki and Martin A. Nowak, "Prelife catalysts and replicators" [abstract], doi:10.1098/rspb.2009.1136, p3783-3790 v276, Proc. R. Soc. B, Nov (online 19 Aug) 2009. "We model prelife as a binary soup of active monomers that form random polymers."
Anna C. Balazs and Irving R. Epstein, "Emergent or Just Complex?" [summary], doi:10.1126/science.1178323, Science, 25 Sep 2009. "The scope of the conference is exemplified by S. Rasmussen's characterization of hydrogen as 'a colorless, odorless gas, which, given enough time, turns into people.'"
14 Sep 2009: If we didn't know about life we wouldn't believe it — Richard Dawkins.
26 Aug 2009: "The Origin of Life on Earth" in a Scientific American Special Issue: "Understanding Origins".
UV light and the origin of life is the subject of a Reply from Armen Y. Mulkidjanian pointing us to papers about the Zinc world, 24 Aug 2009.
Impressions from the San Sebastian meeting Open Questions in the Origin of Life (OQOL), comments by Pier-Luigi Luisi and Andrew Pohorille, NASA Astrobiology Institute (+SpaceRef.com), 15 Jun 2009.
Yasuyuki Ura et al., "Self-Assembling Sequence-Adaptive Peptide Nucleic Acids" [abstract], doi:10.1126/science.1174577, Science, online 11 Jun 2009. Also see a press release: Team Creates Simple Chemical System that Mimics DNA, The Scripps Research Institute, 11 Jun 2009; and commentary: DNA-like Molecule Replicates Without Help, by Robert F. Service, ScienceNOW Daily News, 11 Jun 2009; and Tantalizing clues to the chemical origins of life, by Katharine Sanderson, Nature, online 12 Jun 2009.
Antonio Lazcano, "Mind the Gap!," doi:10.1371/journal.pbio.1000122, v 7 n 6: e122, PLoS Biol., 2 Jun 2009: Review of Protocells: Bridging nonliving and living matter, S Rasmussen et al., eds., Cambridge (Massachusetts): MIT Press, 2008.
John Whitfield, "Origin of life: Nascence man" [link], doi:10.1038/459316a, p 316-319 v 459, Nature, 21 May 2009. "Like an alchemist of yore, Mike Russell is taking basic elements and trying to transform them — not into gold, but into the stirrings of life...."
RNA world easier to make by Richard Van Noorden, doi:10.1038/news.2009.471, Nature.com, 13 May 2009.
Matthew W. Powner et al., "Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions" [abstract | Editor's Summary], doi:10.1038/nature08013, p 239-242 v 459, Nature; and commentary by Jack W. Szostak, "Origins of life: Systems chemistry on early Earth" [html], doi:10.1038/459171a, p 171-172 v 459, Nature, 14 May 2009.
Calculating The Odds That Life Could Begin By Chance by Dave Deamer, ScientificBlogging.com, 30 Apr 2009.
28 Apr 2009: Life is nothing but an electron looking for a place to rest.
Tracey A. Lincoln and Gerald F. Joyce, "Self-Sustained Replication of an RNA Enzyme" [abstract], doi:10.1126/science.1167856, Science, online 8 Jan 2009. "Populations of various cross-replicating enzymes were constructed. ...Many such model systems could be constructed...." Also see commentary: The Immortal Molecule, by Mark Schrope, v9 n1, News & Views, Scripps Research Institute