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Moved page from wikipedia:en:Miller–Urey experiment (history)
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{{short description|Chemical experiment that simulated conditions on the early Earth and tested the origin of life}}
[[File:MUexperiment.png|thumb|upright=1.5|The experiment]]
The experiment
实验
The '''Miller–Urey experiment'''<ref>{{cite journal |vauthors=Hill HG, Nuth JA |title=The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems |journal=Astrobiology |volume=3 |issue=2 |pages=291–304 |year=2003 |pmid=14577878 |doi=10.1089/153110703769016389|bibcode = 2003AsBio...3..291H}}</ref> (or '''Miller experiment''')<ref>{{cite journal | title=The analysis of comet mass spectrometric data |author1=Balm SP |author2=Hare J.P. |author3=Kroto HW | journal=Space Science Reviews| year=1991| volume=56|issue=1–2 | pages=185–9 |doi=10.1007/BF00178408 | bibcode=1991SSRv...56..185B|url=https://www.semanticscholar.org/paper/9bce3627fcb31bac372e6610472e59008703ec4b }}</ref> was a chemical [[experiment]] that simulated the conditions thought at the time (1952) to be present on the [[early Earth]] and tested the [[abiogenesis|chemical origin of life]] under those conditions. The experiment at the time supported [[Alexander Oparin]]'s and [[J. B. S. Haldane]]'s hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex [[organic compound]]s from simpler inorganic precursors. Considered to be the classic experiment investigating [[abiogenesis]], it was performed in 1952 by [[Stanley Miller]], supervised by [[Harold Urey]] at the [[University of Chicago]], and published the following year.<ref name=miller1953>{{cite journal |last=Miller |first=Stanley L. |url=http://www.abenteuer-universum.de/pdf/miller_1953.pdf |title=Production of Amino Acids Under Possible Primitive Earth Conditions |journal=[[Science (journal)|Science]] |year=1953 |volume=117 |pages=528–9 |doi=10.1126/science.117.3046.528 |pmid=13056598 |issue=3046 |bibcode=1953Sci...117..528M |url-status=dead |archiveurl=https://web.archive.org/web/20120317062622/http://www.abenteuer-universum.de/pdf/miller_1953.pdf |archivedate=2012-03-17 |access-date=2011-01-17 }}</ref><ref>{{cite journal |last=Miller |first=Stanley L. |author2=Harold C. Urey |title=Organic Compound Synthesis on the Primitive Earth |journal=[[Science (journal)|Science]] |year=1959 |volume=130 |pages=245–51 |doi=10.1126/science.130.3370.245 |pmid=13668555 |issue=3370|bibcode = 1959Sci...130..245M}} Miller states that he made "A more complete analysis of the products" in the 1953 experiment, listing additional results.</ref><ref>{{cite journal |title=The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry |author1=A. Lazcano |author2=J. L. Bada |journal=Origins of Life and Evolution of Biospheres |volume=33 |year=2004 |pages=235–242 |doi=10.1023/A:1024807125069 |pmid=14515862 |issue=3|url=https://www.semanticscholar.org/paper/beda7cb912470cec6e1bf2d13535edeedf6c5b16 |bibcode=2003OLEB...33..235L }}</ref>
The Miller–Urey experiment More recent evidence suggests that Earth's original atmosphere might have had a composition different from the gas used in the Miller experiment, but prebiotic experiments continue to produce racemic mixtures of simple-to-complex compounds under varying conditions. The boiling flask was then removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using paper chromatography, Miller identified five amino acids present in the solution: glycine, α-alanine and β-alanine were positively identified, while aspartic acid and α-aminobutyric acid (AABA) were less certain, due to the spots being faint.
Miller-Urey 实验更新的证据表明，地球原始大气层的成分可能与 Miller 实验中使用的气体有所不同，但生命起源前实验在不同条件下继续产生简单到复杂化合物的外消旋混合物。然后取出烧瓶，加入氯化汞以防止微生物污染。通过加入氢氧化钡和硫酸，蒸发去除杂质，停止了反应。使用纸色谱法，Miller 鉴定出溶液中存在的5种氨基酸: 甘氨酸、 α- 丙氨酸和 β- 丙氨酸，而天冬氨酸和 α- 氨基丁酸则不那么确定，因为斑点很模糊。
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different [[amino acid]]s produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in the genetic code.<ref name="BBC"/> More recent evidence suggests that Earth's original atmosphere might have had a composition different from the gas used in the Miller experiment, but prebiotic experiments continue to produce [[racemic mixture]]s of simple-to-complex compounds under varying conditions.<ref name=bada2013>{{cite journal|last1=Bada|first1=Jeffrey L.|title=New insights into prebiotic chemistry from Stanley Miller's spark discharge experiments|journal=Chemical Society Reviews|year=2013|volume=42|issue=5|pages=2186–96|doi=10.1039/c3cs35433d|pmid=23340907|url=https://semanticscholar.org/paper/6f463e8a3611fa7f25c143991dfddac49c396b73}}</ref>
In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids." the 2008 re-analysis of vials from the volcanic spark discharge experiment,
在1996年的一次采访中，斯坦利 · 米勒回忆了自己毕生的实验，他说: “只要在一个基本的前生命实验中点燃火花，就能产生20种氨基酸中的11种。”2008年对来自火山火花放电实验的瓶子的重新分析,
! scope="col" | Volcanic spark discharge<br/>
!火山火花放电 < br/>
== Experiment ==
! scope="col" | H<sub>2</sub>S-rich spark discharge<br/>
!范围 = “ col” | h < sub > 2 </sub > 富 s 火花放电 < br/>
[[File:Miller-Urey experiment - Work by the C3BC consortium, licensed under CC-BY-3.0.webm|thumb|Descriptive video of the experiment]]
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The experiment used [[water]] (H<sub>2</sub>O), [[methane]] (CH<sub>4</sub>), [[ammonia]] (NH<sub>3</sub>), and [[hydrogen]] (H<sub>2</sub>). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of water. The water in the smaller flask was heated to induce [[evaporation]], and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate [[lightning]] in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.
|Glycine
| 甘氨酸
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After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.<ref name=miller1953/> The boiling flask was then removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using [[paper chromatography]], Miller identified five amino acids present in the solution: [[glycine]], [[alanine|α-alanine]] and [[beta-Alanine|β-alanine]] were positively identified, while [[aspartic acid]] and [[alpha-Aminobutyric acid|α-aminobutyric acid]] (AABA) were less certain, due to the spots being faint.<ref name=miller1953/>
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In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids."<ref>{{cite web|url=http://www.accessexcellence.org/WN/NM/miller.php |title=Exobiology: An Interview with Stanley L. Miller |publisher=Accessexcellence.org |archiveurl=https://web.archive.org/web/20080518054852/http://www.accessexcellence.org/WN/NM/miller.php |archivedate=May 18, 2008 |accessdate=2009-08-20}}</ref>
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The original experiment remained in 2017 under the care of Miller and Urey's former student [[Jeffrey Bada]], a professor at the [[University of California, San Diego|UCSD]], [[Scripps Institution of Oceanography]].<ref>{{cite news |url=https://www.nytimes.com/2010/05/18/science/18conv.html |title=A Conversation With Jeffrey L. Bada: A Marine Chemist Studies How Life Began |newspaper=nytimes.com |date=2010-05-17 |first=Claudia |last=Dreifus |authorlink=Claudia Dreifus |url-status=live |archiveurl=https://web.archive.org/web/20170118034218/http://www.nytimes.com/2010/05/18/science/18conv.html |archivedate=2017-01-18 }}</ref> {{asof|2013}}, the apparatus used to conduct the experiment was on display at the [[Denver Museum of Nature and Science]].<ref>{{cite news|url=http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus | title=Astrobiology Collection: Miller-Urey Apparatus |archiveurl=https://web.archive.org/web/20130524090309/http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus/ |archivedate=2013-05-24 |publisher=Denver Museum of Nature & Science }}</ref>{{update after|2020|4|14}}
|α-Alanine
|α-Alanine
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==Chemistry of experiment==
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One-step reactions among the mixture components can produce [[hydrogen cyanide]] (HCN), [[formaldehyde]] (CH<sub>2</sub>O),<ref>https://www.webcitation.org/query?url=http://www.geocities.com/capecanaveral/lab/2948/orgel.html&date=2009-10-25+16:53:26 Origin of Life on Earth by Leslie E. Orgel</ref><ref>{{Cite book |url=http://books.nap.edu/openbook.php?record_id=11860&page=85 |title=Read "Exploring Organic Environments in the Solar System" at NAP.edu |accessdate=2008-10-25 |url-status=live |archiveurl=https://web.archive.org/web/20090621053626/http://books.nap.edu/openbook.php?record_id=11860&page=85 |archivedate=2009-06-21 |doi=10.17226/11860 |year=2007 |isbn=978-0-309-10235-3 |last1=Council |first1=National Research |last2=Studies |first2=Division on Earth Life |last3=Technology |first3=Board on Chemical Sciences and |last4=Sciences |first4=Division on Engineering Physical |last5=Board |first5=Space Studies |last6=System |first6=Task Group on Organic Environments in the Solar }} Exploring Organic Environments in the Solar System (2007)</ref> and other active intermediate compounds ([[acetylene]], [[cyanoacetylene]], etc.):{{Citation needed|date=June 2016}}
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: CO<sub>2</sub> → CO + [O] (atomic oxygen)
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: CH<sub>4</sub> + 2[O] → CH<sub>2</sub>O + H<sub>2</sub>O
|β-Alanine
|β-Alanine
: CO + NH<sub>3</sub> → HCN + H<sub>2</sub>O
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: CH<sub>4</sub> + NH<sub>3</sub> → HCN + 3H<sub>2</sub> ([[BMA process]])
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The formaldehyde, ammonia, and HCN then react by [[Strecker synthesis]] to form amino acids and other biomolecules:
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: CH<sub>2</sub>O + HCN + NH<sub>3</sub> → NH<sub>2</sub>-CH<sub>2</sub>-CN + H<sub>2</sub>O
|Aspartic acid
天冬氨酸
: NH<sub>2</sub>-CH<sub>2</sub>-CN + 2H<sub>2</sub>O → NH<sub>3</sub> + NH<sub>2</sub>-CH<sub>2</sub>-COOH ([[glycine]])
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Furthermore, water and formaldehyde can react, via [[Formose reaction|Butlerov's reaction]] to produce various [[sugar]]s like [[ribose]].
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The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.
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|α-Aminobutyric acid
|α-Aminobutyric acid
==Other experiments==
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This experiment inspired many others. In 1961, [[Joan Oró]] found that the [[nucleotide]] base [[adenine]] could be made from [[hydrogen cyanide]] (HCN) and [[ammonia]] in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.<ref>{{cite journal |vauthors=Oró J, Kimball AP |title=Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide |journal=Archives of Biochemistry and Biophysics |volume=94|issue=2 |pages=217–27 |date=August 1961 |pmid=13731263 |doi=10.1016/0003-9861(61)90033-9}}</ref>
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Also, many amino acids are formed from HCN and ammonia under these conditions.<ref>{{cite journal |vauthors=Oró J, Kamat SS |title=Amino-acid synthesis from hydrogen cyanide under possible primitive earth conditions |journal=Nature |volume=190 |issue= 4774|pages=442–3 |date=April 1961 |pmid=13731262 |doi=10.1038/190442a0|bibcode = 1961Natur.190..442O |url=https://www.semanticscholar.org/paper/1aea2775f328d439e5bb65e61fdf3b988d829052 }}</ref>
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Experiments conducted later showed that the other [[Nucleobase|RNA and DNA nucleobases]] could be obtained through simulated prebiotic chemistry with a [[reducing atmosphere]].<ref>{{cite book | title=Origins of Prebiological Systems and of Their Molecular Matrices| editor= Fox SW| author=Oró J| year=1967| pages=137| publisher=New York Academic Press}}</ref>
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There also had been similar electric discharge experiments related to the [[origin of life]] contemporaneous with Miller–Urey. An article in ''[[The New York Times]]'' (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at [[The Ohio State University]], before the Miller ''Science'' paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis." The article describes other early earth experiments being done by MacNevin. It is not clear if he ever published any of these results in the primary scientific literature.<ref>{{cite book | title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference | publisher=[[Springer-Verlag]] | author=Krehl, Peter O. K. | year=2009 | pages=603}}</ref><!--is it not clear because academics have researched this and somehow can't tell, or is it just not clear to the Wikipedia contributor from reading only the NYT article?-->
|Serine
| Serine
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K. A. Wilde submitted a paper to ''Science'' on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953.<ref>{{cite journal |last=Wilde |first=Kenneth A. |authorlink= |first2=Bruno J. |last2=Zwolinski |first3=Ransom B. |last3=Parlin |date=July 1953 |title=The Reaction Occurring in CO<sub>2</sub>, <sub>2</sub>O Mixtures in a High-Frequency Electric Arc |journal=[[Science (journal)|Science]] |volume=118 |issue=3054 |pages=43–44 |id= |doi=10.1126/science.118.3054.43-a |pmid=13076175 |bibcode=1953Sci...118...43W |df= }}</ref> Wilde used voltages up to only 600 V on a binary mixture of [[carbon dioxide]] (CO<sub>2</sub>) and water in a flow system. He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.
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Other researchers were studying [[Ultraviolet|UV]]-[[photolysis]] of water vapor with [[carbon monoxide]]. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.<ref>[https://doi.org/10.1007%2FBF00931407 Synthesis of organic compounds from carbon monoxide and water by UV photolysis] ''Origins of Life''. December 1978, Volume 9, Issue 2, pp 93-101
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Akiva Bar-nun, Hyman Hartman.</ref>
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More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at [[Scripps Institution of Oceanography]] of the [[University of California, San Diego]] were similar to those performed by Miller. However, Bada noted that in current models of early Earth conditions, carbon dioxide and [[nitrogen]] (N<sub>2</sub>) create [[nitrite]]s, which destroy amino acids as fast as they form. <!--However, the early Earth may have had significant amounts of iron and [[carbonate minerals]] able to neutralize the effects of the nitrites.{{Citation needed|date=January 2016}} --> <!-- Please find a scientific paper that makes this statement before removing the tag -- and then the remark may be visible again --> When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen.<ref name=Fox>{{Cite news |last=Fox |first=Douglas |date=2007-03-28 |title=Primordial Soup's On: Scientists Repeat Evolution's Most Famous Experiment |periodical=Scientific American |series=History of Science |publisher=Scientific American Inc. |url=http://www.sciam.com/article.cfm?id=primordial-soup-urey-miller-evolution-experiment-repeated |accessdate=2008-07-09 }}<br>{{Cite journal | last1 = Cleaves | first1 = H. J. | last2 = Chalmers | first2 = J. H. | last3 = Lazcano | first3 = A. | last4 = Miller | first4 = S. L. | last5 = Bada | first5 = J. L. | title = A Reassessment of Prebiotic Organic Synthesis in Neutral Planetary Atmospheres | doi = 10.1007/s11084-007-9120-3 | journal = Origins of Life and Evolution of Biospheres | volume = 38 | issue = 2 | pages = 105–115 | year = 2008 | pmid = 18204914| bibcode = 2008OLEB...38..105C |url=http://www.astro.ulg.ac.be/~mouchet/BIOC0701-1/Cleaves-etal-2008.pdf |url-status=dead |archive-url=https://web.archive.org/web/20131107134729/http://www.astro.ulg.ac.be/~mouchet/BIOC0701-1/Cleaves-etal-2008.pdf |archive-date=2013-11-07 }}</ref>
|Isoserine
| 异丝氨酸
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==Earth's early atmosphere==
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Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, [[hydrogen sulfide]] (H<sub>2</sub>S), and [[sulfur dioxide]] (SO<sub>2</sub>) into the atmosphere.<ref name=Green>{{Cite journal|last=Green|first=Jack|title=Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife|journal=International Journal of Molecular Sciences|year=2011|volume=12|issue=9|pages=6051–6076|doi=10.3390/ijms12096051|pmid=22016644|pmc=3189768|ref=harv}}</ref> Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D [[enantiomer]]s) and experiments since have shown that "in the lab the two versions are equally likely to appear";<ref name="NS">{{Cite news |date=2006-06-02 |title=Right-handed amino acids were left behind |periodical=[[New Scientist]] |publisher=Reed Business Information Ltd |issue=2554 |pages=18 |url=https://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |accessdate=2008-07-09 |url-status=live |archiveurl=https://web.archive.org/web/20081024211531/http://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |archivedate=2008-10-24 }}</ref> however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.<ref>{{cite journal |last=Kojo |first=Shosuke |first2=Hiromi |last2=Uchino |first3=Mayu |last3=Yoshimura |first4=Kyoko |last4=Tanaka |date=October 2004 |title=Racemic D,L-asparagine causes enantiomeric excess of other coexisting racemic D,L-amino acids during recrystallization: a hypothesis accounting for the origin of L-amino acids in the biosphere |journal=Chemical Communications |volume= |issue=19 |pages=2146–2147 |pmid=15467844 |doi=10.1039/b409941a}}</ref>
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Originally it was thought that the primitive [[secondary atmosphere]] contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO<sub>2</sub> with perhaps some CO and the nitrogen mostly N<sub>2</sub>. In practice gas mixtures containing CO, CO<sub>2</sub>, N<sub>2</sub>, etc. give much the same products as those containing CH<sub>4</sub> and NH<sub>3</sub> so long as there is no O<sub>2</sub>. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, [[hydroxy acid|hydroxyacids]], purines, pyrimidines, and sugars have been made in variants of the Miller experiment.<ref name=bada2013/><ref>{{cite journal|last1=Ruiz-Mirazo|first1=Kepa|last2=Briones|first2=Carlos|last3=de la Escosura|first3=Andrés|title=Prebiotic Systems Chemistry: New Perspectives for the Origins of Life|journal=Chemical Reviews|year=2014|volume=114|issue=1|pages=285–366|doi=10.1021/cr2004844|pmid=24171674}}</ref>
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|α-Aminoisobutyric acid
|α-Aminoisobutyric acid
More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature.<ref>{{cite web |url=http://newsrelease.uwaterloo.ca/news.php?id=4348 |accessdate=2005-12-17 |title=Early Earth atmosphere favorable to life: study |publisher=University of Waterloo |url-status=dead |archiveurl=https://web.archive.org/web/20051214230357/http://newsrelease.uwaterloo.ca/news.php?id=4348 |archivedate=2005-12-14 }}</ref> One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.<ref>{{cite web |url=http://news-info.wustl.edu/news/page/normal/5513.html |accessdate=2005-12-17 |title=Calculations favor reducing atmosphere for early earth – Was Miller–Urey experiment correct? |first=Tony |last=Fitzpatrick |publisher=Washington University in St. Louis |year=2005 |url-status=dead |archiveurl=https://web.archive.org/web/20080720174657/http://news-info.wustl.edu/news/page/normal/5513.html |archivedate=2008-07-20 }}</ref>
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In contrast to the general notion of early earth's reducing atmosphere, researchers at the [[Rensselaer Polytechnic Institute]] in New York reported the possibility of oxygen available around 4.3 billion years ago. Their study reported in 2011 on the assessment of Hadean [[zircons]] from the earth's interior ([[magma]]) indicated the presence of oxygen traces similar to modern-day lavas.<ref>{{cite journal|last1=Trail|first1=Dustin|last2=Watson|first2=E. Bruce|last3=Tailby|first3=Nicholas D.|title=The oxidation state of Hadean magmas and implications for early Earth's atmosphere|journal=Nature|year=2011|volume=480|issue=7375|pages=79–82|doi=10.1038/nature10655|pmid=22129728|bibcode=2011Natur.480...79T|url=https://www.semanticscholar.org/paper/e87ff5db353f56ac40649b2a4ca618f3c2067cdb}}</ref> This study suggests that oxygen could have been released in the earth's atmosphere earlier than generally believed.<ref>{{cite journal|last1=Scaillet|first1=Bruno|last2=Gaillard|first2=Fabrice|title=Earth science: Redox state of early magmas|journal=Nature|date=2011|volume=480|issue=7375|pages=48–49|doi=10.1038/480048a|pmid=22129723|bibcode=2011Natur.480...48S|url=https://hal.archives-ouvertes.fr/file/index/docid/648930/filename/Scaillet-Nature2-2011.pdf|url-status=live|archiveurl=https://web.archive.org/web/20171026110646/https://hal.archives-ouvertes.fr/file/index/docid/648930/filename/Scaillet-Nature2-2011.pdf|archivedate=2017-10-26|citeseerx=10.1.1.659.2086}}</ref>
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==Extraterrestrial sources==
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Conditions similar to those of the Miller–Urey experiments are present in other regions of the [[solar system]], often substituting [[ultraviolet]] light for lightning as the energy source for chemical reactions.<ref>{{cite journal|last1=Nunn|first1=JF|title=Evolution of the atmosphere|journal=Proceedings of the Geologists' Association. Geologists' Association|year=1998|volume=109|issue=1|pages=1–13|pmid=11543127|doi=10.1016/s0016-7878(98)80001-1}}</ref><ref>{{cite journal|last1=Raulin|first1=F|last2=Bossard|first2=A|title=Organic syntheses in gas phase and chemical evolution in planetary atmospheres.|journal=Advances in Space Research|year=1984|volume=4|issue=12|pages=75–82|pmid=11537798|doi=10.1016/0273-1177(84)90547-7|bibcode=1984AdSpR...4...75R}}</ref><ref>{{cite journal|last1=Raulin|first1=François|last2=Brassé|first2=Coralie|last3=Poch|first3=Olivier|last4=Coll|first4=Patrice|title=Prebiotic-like chemistry on Titan|journal= Chemical Society Reviews|year=2012|volume=41|issue=16|pages=5380–93|doi=10.1039/c2cs35014a|pmid=22481630}}</ref> The [[Murchison meteorite]] that fell near [[Murchison, Victoria]], Australia in 1969 was found to contain over 90 different amino acids, nineteen of which are found in Earth life. [[Comet]]s and other [[Trans-Neptunian object|icy outer-solar-system bodies]] are thought to contain large amounts of complex carbon compounds (such as [[tholin]]s) formed by these processes, darkening surfaces of these bodies.<ref>{{cite journal |vauthors=Thompson WR, Murray BG, Khare BN, Sagan C |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: applications to the outer solar system |journal=Journal of Geophysical Research |volume=92 |issue=A13 |pages=14933–47 |date=December 1987 |pmid=11542127 |doi=10.1029/JA092iA13p14933 |bibcode=1987JGR....9214933T|title-link=methane clathrate }}</ref> The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed.<ref>{{cite journal|last=PIERAZZO|first=E.|author2=CHYBA C.F.|title=Amino acid survival in large cometary impacts|journal=Meteoritics & Planetary Science|year=2010|volume=34|issue=6|pages=909–918|doi=10.1111/j.1945-5100.1999.tb01409.x|bibcode=1999M&PS...34..909P}}</ref> This has been used to infer an origin of life outside of Earth: the [[panspermia]] hypothesis.
|β-Aminoisobutyric acid
|β-Aminoisobutyric acid
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==Recent related studies==
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In recent years, studies have been made of the [[amino acid]] composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated [[species]], assumed to share only the [[last universal ancestor]] (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.<ref>{{cite journal |author1=Brooks D.J. |author2=Fresco J.R. |author3=Lesk A.M. |author4=Singh M. |url=http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |title=Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code |journal=Molecular Biology and Evolution |date=October 1, 2002 |volume=19 |pages=1645–55 |pmid=12270892 |issue=10 |doi=10.1093/oxfordjournals.molbev.a003988 |url-status=dead |archiveurl=https://web.archive.org/web/20041213094516/http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |archivedate=December 13, 2004 |doi-access=free }}</ref>
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[[Jeffrey Bada]], himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.<ref name="BBC">{{cite web |website=BBC Four |url=http://www.bbc.co.uk/programmes/b00mbvfh |title=The Spark of Life |url-status=live |archive-url=https://web.archive.org/web/20101113011054/http://www.bbc.co.uk/programmes/b00mbvfh |archive-date=2010-11-13 |postscript=. TV Documentary. |date=26 August 2009}}</ref>
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|β-Aminobutyric acid
|β-Aminobutyric acid
In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of [[Charles Darwin]]'s envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of [[volcano|volcanic]] eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using [[high-performance liquid chromatography]] and [[mass spectrometry]], the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 [[amine]]s and many [[hydroxylate]]d molecules, which could have been formed by [[hydroxyl radical]]s produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of [[carbonyl sulfide]] there could have helped these molecules form [[peptide]]s.<ref name=Johnson2008>{{cite journal |vauthors=Johnson AP, Cleaves HJ, Dworkin JP, Glavin DP, Lazcano A, Bada JL |title=The Miller volcanic spark discharge experiment |journal=Science |volume=322 |issue=5900 |pages=404 |date=October 2008 |pmid=18927386 |doi=10.1126/science.1161527|bibcode = 2008Sci...322..404J }}</ref><ref>{{cite web | title='Lost' Miller–Urey Experiment Created More Of Life's Building Blocks | date=October 17, 2008 | website=Science Daily | url=https://www.sciencedaily.com/releases/2008/10/081016141411.htm | accessdate=2008-10-18 | url-status=live | archiveurl=https://web.archive.org/web/20081019111114/http://www.sciencedaily.com/releases/2008/10/081016141411.htm | archivedate=October 19, 2008 }}</ref>
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The main problem of theories based around [[amino acids]] is the difficulty in obtaining spontaneous formation of peptides. Since [[John Desmond Bernal]]'s suggestion that clay surfaces could have played a role in [[abiogenesis]]<ref name=Bernal1949>{{cite journal |vauthors=Bernal JD |title=The physical basis of life |journal=Proc. Phys. Soc. A | issue=9 |volume=62 |pages=537–558 |date=1949|doi=10.1088/0370-1298/62/9/301 |bibcode=1949PPSA...62..537B }}</ref>, scientific efforts have been dedicated to investigating clay-mediated [[peptide bond]] formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators <ref name="RT-2018">{{cite news | publisher=RT | url=https://www.rt.com/news/416581-scientists-unlock-life-puzzle-protein/ | title='How did life form from rocks?' Protein puzzle reveals secrets of Earth's evolution | date=January 2017}}</ref><ref name="Erastova2017">{{cite journal |vauthors=Erastova V, Degiacomi MT, Fraser D, Greenwell HC |title=Mineral surface chemistry control for origin of prebiotic peptides |journal=Nature Communications |volume=8 |issue=1 |pages=2033 |date=December 2017|pmid=29229963 |pmc=5725419 |doi=10.1038/s41467-017-02248-y |bibcode=2017NatCo...8.2033E }}</ref> suggested that peptides could form at the interlayers of [[layered double hydroxides]] such as [[green rust]] in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a [[ribosome]]-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.
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In October 2018, researchers at [[McMaster University]] on behalf of the [[Origins Institute]] announced the development of a new technology, called a ''[[Planet Simulator]]'', to help study the [[origin of life]] on planet [[Earth]] and beyond.<ref name="BW-20181004">{{cite news |last=Balch |first=Erica |title=Ground-breaking lab poised to unlock the mystery of the origins of life on Earth and beyond |url=https://brighterworld.mcmaster.ca/articles/ground-breaking-lab-poised-to-unlock-the-mystery-of-the-origins-of-life-on-earth-and-beyond/ |date=4 October 2018 |work=[[McMaster University]] |accessdate=4 October 2018 }}</ref><ref name="EA-20181004">{{cite news |author=Staff |title=Ground-breaking lab poised to unlock the mystery of the origins of life |url=https://www.eurekalert.org/pub_releases/2018-10/mu-glp100418.php |date=4 October 2018 |work=[[EurekAlert!]] |accessdate=14 October 2018 }}</ref><ref name="IVG-2018">{{cite web |author=Staff |title=Planet Simulator |url=https://www.intravisiongroup.com/planet-simulator |date=2018 |work=IntraVisionGroup.com |accessdate=14 October 2018 }}</ref><ref name="ES-209181014">{{cite web |last=Anderson |first=Paul Scott |title=New technology may help solve mystery of life's origins - How did life on Earth begin? A new technology, called Planet Simulator, might finally help solve the mystery. |url=http://earthsky.org/space/new-technology-solve-mystery-of-lifes-origins |date=14 October 2018 |work=[[EarthSky]] |accessdate=14 October 2018 }}</ref>
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|γ-Aminobutyric acid
|γ-Aminobutyric acid
==Amino acids identified==
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{{Category see also|Chemical synthesis of amino acids}}
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Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as published by Miller in 1953,<ref name=miller1953/> the 2008 re-analysis of vials from the volcanic spark discharge experiment,<ref>{{cite web|last1=Myers|first1=P. Z.|title=Old scientists never clean out their refrigerators|url=http://scienceblogs.com/pharyngula/2008/10/old_scientists_never_clean_out.php|website=Pharyngula|accessdate=7 April 2016|archiveurl=https://web.archive.org/web/20081017231050/http://scienceblogs.com/pharyngula/2008/10/old_scientists_never_clean_out.php|archivedate=October 17, 2008|date=October 16, 2008}}</ref> and the 2010 re-analysis of vials from the H<sub>2</sub>S-rich spark discharge experiment.<ref>{{cite journal|title=Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment|journal=Proceedings of the National Academy of Sciences|date=February 14, 2011|volume=108|issue=14|doi=10.1073/pnas.1019191108|pmid=21422282|pmc=3078417|pages=5526–31|last1=Parker|first1=ET|last2=Cleaves|first2=HJ|last3=Dworkin|first3=JP|display-authors=etal |bibcode=2011PNAS..108.5526P|df=}}</ref>
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{|class="wikitable sortable" style="text-align:right"
|Valine
瓦林
|-
|
|
! scope="col" rowspan="2" | Amino acid
|
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! scope="col" colspan="3" | Produced in experiment
|
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! scope="col" rowspan="2" | [[Proteinogenic]]
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|-
|-
|-
! scope="col" | Miller–Urey<br/>{{small|(1952)}}
|Isovaline
异缬氨酸
! scope="col" | Volcanic spark discharge<br/>{{small|(2008)}}
|
|
! scope="col" | H<sub>2</sub>S-rich spark discharge<br/>{{small|(2010)}}
|
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|-
|
|
|[[Glycine]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|Glutamic acid
谷氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[alanine|α-Alanine]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|Norvaline
诺瓦林
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[beta-Alanine|β-Alanine]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|α-Aminoadipic acid
Α-氨基己二酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
|
|[[Aspartic acid]]
|
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| {{ya}}
|-
|-
| {{ya}}
|Homoserine
高丝氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[alpha-Aminobutyric acid|α-Aminobutyric acid]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|2-Methylserine
| 2- 甲基丝氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[Serine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|β-Hydroxyaspartic acid
|β-Hydroxyaspartic acid
| {{ya}}
|
|
| {{yes}}
|
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|-
|
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|[[Isoserine]]
|
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| {{na}}
|-
|-
| {{ya}}
|Ornithine
鸟氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[2-Aminoisobutyric acid|α-Aminoisobutyric acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|2-Methylglutamic acid
| 2- 甲基谷氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[3-Aminoisobutyric acid|β-Aminoisobutyric acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Phenylalanine
| 苯丙氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[beta-Aminobutyric acid|β-Aminobutyric acid]]
|
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| {{na}}
|-
|-
| {{ya}}
|Homocysteic acid
高同型半胱氨酸
| {{ya}}
|
|
| {{no}}
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|-
|
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|[[gamma-Aminobutyric acid|γ-Aminobutyric acid]]
|
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| {{na}}
|-
|-
| {{ya}}
|S-Methylcysteine
S- 甲基半胱氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[Valine]]
|
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| {{na}}
|-
|-
| {{ya}}
|Methionine
| 蛋氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
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|[[Isovaline]]
|
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| {{na}}
|-
|-
| {{ya}}
|Methionine sulfoxide
蛋氨酸亚砜
| {{ya}}
|
|
| {{no}}
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|-
|
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|[[Glutamic acid]]
|
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| {{na}}
|-
|-
| {{ya}}
|Methionine sulfone
蛋氨酸砜
| {{ya}}
|
|
| {{yes}}
|
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|-
|
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|[[Norvaline]]
|
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| {{na}}
|-
|-
| {{ya}}
|Isoleucine
异亮氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[alpha-Aminoadipic acid|α-Aminoadipic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Leucine
亮氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[Homoserine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Ethionine
|Ethionine
| {{na}}
|
|
| {{no}}
|
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|-
|
|
|[[2-Methylserine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Cysteine
半胱氨酸
| {{na}}
|
|
| {{no}}
|
|
|-
|
|
|[[3-Hydroxyaspartic acid|β-Hydroxyaspartic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Histidine
| 组氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[Ornithine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Lysine
赖氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
|
|[[2-Methylglutamic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Asparagine
天冬酰胺
| {{na}}
|
|
| {{no}}
|
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|-
|
|
|[[Phenylalanine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Pyrrolysine
| 吡咯赖氨酸
| {{na}}
|
|
| {{yes}}
|
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|-
|
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|[[Homocysteic acid]]
|
|
| {{na}}
|-
|-
| {{na}}
|Proline
| Proline
| {{ya}}
|
|
| {{no}}
|
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|-
|
|
|[[S-methylcysteine|''S''-Methylcysteine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Glutamine
谷氨酰胺
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Methionine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Arginine
精氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Methionine sulfoxide]]
|
|
| {{na}}
|-
|-
| {{na}}
|Threonine
苏氨酸
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Methionine sulfone]]
|
|
| {{na}}
|-
|-
| {{na}}
|Selenocysteine
硒代半胱氨酸
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Isoleucine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Tryptophan
色氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Leucine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Tyrosine
| 酪氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Ethionine]]
|
|
| {{na}}
|}
|}
| {{na}}
| {{ya}}
| {{no}}
|-
|[[Cysteine]]
| {{na}}
| {{na}}
| {{na}}
| {{yes}}
|-
|[[Histidine]]
| {{na}}
| {{na}}
| {{na}}
| {{yes}}
|-
|[[Lysine]]
| {{na}}
| {{na}}
Category:Articles containing video clips
类别: 包含视频剪辑的文章
| {{na}}
Category:Biology experiments
类别: 生物学实验
| {{yes}}
Category:Chemical synthesis of amino acids
类别: 氨基酸的化学合成
|-
Category:Chemistry experiments
类别: 化学实验
|[[Asparagine]]
Category:Origin of life
类别: 生命的起源
| {{na}}
Category:1952 in biology
分类: 1952年生物学
| {{na}}
Category:1953 in biology
分类: 1953年生物学
| {{na}}
Category:2008 in science
分类: 2008年科学
<noinclude>
<small>This page was moved from [[wikipedia:en:Miller–Urey experiment]]. Its edit history can be viewed at [[米勒-尤里实验/edithistory]]</small></noinclude>
[[Category:待整理页面]]
{{short description|Chemical experiment that simulated conditions on the early Earth and tested the origin of life}}
[[File:MUexperiment.png|thumb|upright=1.5|The experiment]]
The experiment
实验
The '''Miller–Urey experiment'''<ref>{{cite journal |vauthors=Hill HG, Nuth JA |title=The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems |journal=Astrobiology |volume=3 |issue=2 |pages=291–304 |year=2003 |pmid=14577878 |doi=10.1089/153110703769016389|bibcode = 2003AsBio...3..291H}}</ref> (or '''Miller experiment''')<ref>{{cite journal | title=The analysis of comet mass spectrometric data |author1=Balm SP |author2=Hare J.P. |author3=Kroto HW | journal=Space Science Reviews| year=1991| volume=56|issue=1–2 | pages=185–9 |doi=10.1007/BF00178408 | bibcode=1991SSRv...56..185B|url=https://www.semanticscholar.org/paper/9bce3627fcb31bac372e6610472e59008703ec4b }}</ref> was a chemical [[experiment]] that simulated the conditions thought at the time (1952) to be present on the [[early Earth]] and tested the [[abiogenesis|chemical origin of life]] under those conditions. The experiment at the time supported [[Alexander Oparin]]'s and [[J. B. S. Haldane]]'s hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex [[organic compound]]s from simpler inorganic precursors. Considered to be the classic experiment investigating [[abiogenesis]], it was performed in 1952 by [[Stanley Miller]], supervised by [[Harold Urey]] at the [[University of Chicago]], and published the following year.<ref name=miller1953>{{cite journal |last=Miller |first=Stanley L. |url=http://www.abenteuer-universum.de/pdf/miller_1953.pdf |title=Production of Amino Acids Under Possible Primitive Earth Conditions |journal=[[Science (journal)|Science]] |year=1953 |volume=117 |pages=528–9 |doi=10.1126/science.117.3046.528 |pmid=13056598 |issue=3046 |bibcode=1953Sci...117..528M |url-status=dead |archiveurl=https://web.archive.org/web/20120317062622/http://www.abenteuer-universum.de/pdf/miller_1953.pdf |archivedate=2012-03-17 |access-date=2011-01-17 }}</ref><ref>{{cite journal |last=Miller |first=Stanley L. |author2=Harold C. Urey |title=Organic Compound Synthesis on the Primitive Earth |journal=[[Science (journal)|Science]] |year=1959 |volume=130 |pages=245–51 |doi=10.1126/science.130.3370.245 |pmid=13668555 |issue=3370|bibcode = 1959Sci...130..245M}} Miller states that he made "A more complete analysis of the products" in the 1953 experiment, listing additional results.</ref><ref>{{cite journal |title=The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry |author1=A. Lazcano |author2=J. L. Bada |journal=Origins of Life and Evolution of Biospheres |volume=33 |year=2004 |pages=235–242 |doi=10.1023/A:1024807125069 |pmid=14515862 |issue=3|url=https://www.semanticscholar.org/paper/beda7cb912470cec6e1bf2d13535edeedf6c5b16 |bibcode=2003OLEB...33..235L }}</ref>
The Miller–Urey experiment More recent evidence suggests that Earth's original atmosphere might have had a composition different from the gas used in the Miller experiment, but prebiotic experiments continue to produce racemic mixtures of simple-to-complex compounds under varying conditions. The boiling flask was then removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using paper chromatography, Miller identified five amino acids present in the solution: glycine, α-alanine and β-alanine were positively identified, while aspartic acid and α-aminobutyric acid (AABA) were less certain, due to the spots being faint.
Miller-Urey 实验更新的证据表明，地球原始大气层的成分可能与 Miller 实验中使用的气体有所不同，但生命起源前实验在不同条件下继续产生简单到复杂化合物的外消旋混合物。然后取出烧瓶，加入氯化汞以防止微生物污染。通过加入氢氧化钡和硫酸，蒸发去除杂质，停止了反应。使用纸色谱法，Miller 鉴定出溶液中存在的5种氨基酸: 甘氨酸、 α- 丙氨酸和 β- 丙氨酸，而天冬氨酸和 α- 氨基丁酸则不那么确定，因为斑点很模糊。
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different [[amino acid]]s produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in the genetic code.<ref name="BBC"/> More recent evidence suggests that Earth's original atmosphere might have had a composition different from the gas used in the Miller experiment, but prebiotic experiments continue to produce [[racemic mixture]]s of simple-to-complex compounds under varying conditions.<ref name=bada2013>{{cite journal|last1=Bada|first1=Jeffrey L.|title=New insights into prebiotic chemistry from Stanley Miller's spark discharge experiments|journal=Chemical Society Reviews|year=2013|volume=42|issue=5|pages=2186–96|doi=10.1039/c3cs35433d|pmid=23340907|url=https://semanticscholar.org/paper/6f463e8a3611fa7f25c143991dfddac49c396b73}}</ref>
In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids." the 2008 re-analysis of vials from the volcanic spark discharge experiment,
在1996年的一次采访中，斯坦利 · 米勒回忆了自己毕生的实验，他说: “只要在一个基本的前生命实验中点燃火花，就能产生20种氨基酸中的11种。”2008年对来自火山火花放电实验的瓶子的重新分析,
! scope="col" | Volcanic spark discharge<br/>
!火山火花放电 < br/>
== Experiment ==
! scope="col" | H<sub>2</sub>S-rich spark discharge<br/>
!范围 = “ col” | h < sub > 2 </sub > 富 s 火花放电 < br/>
[[File:Miller-Urey experiment - Work by the C3BC consortium, licensed under CC-BY-3.0.webm|thumb|Descriptive video of the experiment]]
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The experiment used [[water]] (H<sub>2</sub>O), [[methane]] (CH<sub>4</sub>), [[ammonia]] (NH<sub>3</sub>), and [[hydrogen]] (H<sub>2</sub>). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of water. The water in the smaller flask was heated to induce [[evaporation]], and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate [[lightning]] in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.
|Glycine
| 甘氨酸
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After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.<ref name=miller1953/> The boiling flask was then removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using [[paper chromatography]], Miller identified five amino acids present in the solution: [[glycine]], [[alanine|α-alanine]] and [[beta-Alanine|β-alanine]] were positively identified, while [[aspartic acid]] and [[alpha-Aminobutyric acid|α-aminobutyric acid]] (AABA) were less certain, due to the spots being faint.<ref name=miller1953/>
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In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids."<ref>{{cite web|url=http://www.accessexcellence.org/WN/NM/miller.php |title=Exobiology: An Interview with Stanley L. Miller |publisher=Accessexcellence.org |archiveurl=https://web.archive.org/web/20080518054852/http://www.accessexcellence.org/WN/NM/miller.php |archivedate=May 18, 2008 |accessdate=2009-08-20}}</ref>
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The original experiment remained in 2017 under the care of Miller and Urey's former student [[Jeffrey Bada]], a professor at the [[University of California, San Diego|UCSD]], [[Scripps Institution of Oceanography]].<ref>{{cite news |url=https://www.nytimes.com/2010/05/18/science/18conv.html |title=A Conversation With Jeffrey L. Bada: A Marine Chemist Studies How Life Began |newspaper=nytimes.com |date=2010-05-17 |first=Claudia |last=Dreifus |authorlink=Claudia Dreifus |url-status=live |archiveurl=https://web.archive.org/web/20170118034218/http://www.nytimes.com/2010/05/18/science/18conv.html |archivedate=2017-01-18 }}</ref> {{asof|2013}}, the apparatus used to conduct the experiment was on display at the [[Denver Museum of Nature and Science]].<ref>{{cite news|url=http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus | title=Astrobiology Collection: Miller-Urey Apparatus |archiveurl=https://web.archive.org/web/20130524090309/http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus/ |archivedate=2013-05-24 |publisher=Denver Museum of Nature & Science }}</ref>{{update after|2020|4|14}}
|α-Alanine
|α-Alanine
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==Chemistry of experiment==
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One-step reactions among the mixture components can produce [[hydrogen cyanide]] (HCN), [[formaldehyde]] (CH<sub>2</sub>O),<ref>https://www.webcitation.org/query?url=http://www.geocities.com/capecanaveral/lab/2948/orgel.html&date=2009-10-25+16:53:26 Origin of Life on Earth by Leslie E. Orgel</ref><ref>{{Cite book |url=http://books.nap.edu/openbook.php?record_id=11860&page=85 |title=Read "Exploring Organic Environments in the Solar System" at NAP.edu |accessdate=2008-10-25 |url-status=live |archiveurl=https://web.archive.org/web/20090621053626/http://books.nap.edu/openbook.php?record_id=11860&page=85 |archivedate=2009-06-21 |doi=10.17226/11860 |year=2007 |isbn=978-0-309-10235-3 |last1=Council |first1=National Research |last2=Studies |first2=Division on Earth Life |last3=Technology |first3=Board on Chemical Sciences and |last4=Sciences |first4=Division on Engineering Physical |last5=Board |first5=Space Studies |last6=System |first6=Task Group on Organic Environments in the Solar }} Exploring Organic Environments in the Solar System (2007)</ref> and other active intermediate compounds ([[acetylene]], [[cyanoacetylene]], etc.):{{Citation needed|date=June 2016}}
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: CO<sub>2</sub> → CO + [O] (atomic oxygen)
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: CH<sub>4</sub> + 2[O] → CH<sub>2</sub>O + H<sub>2</sub>O
|β-Alanine
|β-Alanine
: CO + NH<sub>3</sub> → HCN + H<sub>2</sub>O
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: CH<sub>4</sub> + NH<sub>3</sub> → HCN + 3H<sub>2</sub> ([[BMA process]])
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The formaldehyde, ammonia, and HCN then react by [[Strecker synthesis]] to form amino acids and other biomolecules:
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: CH<sub>2</sub>O + HCN + NH<sub>3</sub> → NH<sub>2</sub>-CH<sub>2</sub>-CN + H<sub>2</sub>O
|Aspartic acid
天冬氨酸
: NH<sub>2</sub>-CH<sub>2</sub>-CN + 2H<sub>2</sub>O → NH<sub>3</sub> + NH<sub>2</sub>-CH<sub>2</sub>-COOH ([[glycine]])
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Furthermore, water and formaldehyde can react, via [[Formose reaction|Butlerov's reaction]] to produce various [[sugar]]s like [[ribose]].
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The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.
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|α-Aminobutyric acid
|α-Aminobutyric acid
==Other experiments==
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This experiment inspired many others. In 1961, [[Joan Oró]] found that the [[nucleotide]] base [[adenine]] could be made from [[hydrogen cyanide]] (HCN) and [[ammonia]] in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.<ref>{{cite journal |vauthors=Oró J, Kimball AP |title=Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide |journal=Archives of Biochemistry and Biophysics |volume=94|issue=2 |pages=217–27 |date=August 1961 |pmid=13731263 |doi=10.1016/0003-9861(61)90033-9}}</ref>
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Also, many amino acids are formed from HCN and ammonia under these conditions.<ref>{{cite journal |vauthors=Oró J, Kamat SS |title=Amino-acid synthesis from hydrogen cyanide under possible primitive earth conditions |journal=Nature |volume=190 |issue= 4774|pages=442–3 |date=April 1961 |pmid=13731262 |doi=10.1038/190442a0|bibcode = 1961Natur.190..442O |url=https://www.semanticscholar.org/paper/1aea2775f328d439e5bb65e61fdf3b988d829052 }}</ref>
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Experiments conducted later showed that the other [[Nucleobase|RNA and DNA nucleobases]] could be obtained through simulated prebiotic chemistry with a [[reducing atmosphere]].<ref>{{cite book | title=Origins of Prebiological Systems and of Their Molecular Matrices| editor= Fox SW| author=Oró J| year=1967| pages=137| publisher=New York Academic Press}}</ref>
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There also had been similar electric discharge experiments related to the [[origin of life]] contemporaneous with Miller–Urey. An article in ''[[The New York Times]]'' (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at [[The Ohio State University]], before the Miller ''Science'' paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis." The article describes other early earth experiments being done by MacNevin. It is not clear if he ever published any of these results in the primary scientific literature.<ref>{{cite book | title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference | publisher=[[Springer-Verlag]] | author=Krehl, Peter O. K. | year=2009 | pages=603}}</ref><!--is it not clear because academics have researched this and somehow can't tell, or is it just not clear to the Wikipedia contributor from reading only the NYT article?-->
|Serine
| Serine
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K. A. Wilde submitted a paper to ''Science'' on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953.<ref>{{cite journal |last=Wilde |first=Kenneth A. |authorlink= |first2=Bruno J. |last2=Zwolinski |first3=Ransom B. |last3=Parlin |date=July 1953 |title=The Reaction Occurring in CO<sub>2</sub>, <sub>2</sub>O Mixtures in a High-Frequency Electric Arc |journal=[[Science (journal)|Science]] |volume=118 |issue=3054 |pages=43–44 |id= |doi=10.1126/science.118.3054.43-a |pmid=13076175 |bibcode=1953Sci...118...43W |df= }}</ref> Wilde used voltages up to only 600 V on a binary mixture of [[carbon dioxide]] (CO<sub>2</sub>) and water in a flow system. He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.
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Other researchers were studying [[Ultraviolet|UV]]-[[photolysis]] of water vapor with [[carbon monoxide]]. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.<ref>[https://doi.org/10.1007%2FBF00931407 Synthesis of organic compounds from carbon monoxide and water by UV photolysis] ''Origins of Life''. December 1978, Volume 9, Issue 2, pp 93-101
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Akiva Bar-nun, Hyman Hartman.</ref>
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More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at [[Scripps Institution of Oceanography]] of the [[University of California, San Diego]] were similar to those performed by Miller. However, Bada noted that in current models of early Earth conditions, carbon dioxide and [[nitrogen]] (N<sub>2</sub>) create [[nitrite]]s, which destroy amino acids as fast as they form. <!--However, the early Earth may have had significant amounts of iron and [[carbonate minerals]] able to neutralize the effects of the nitrites.{{Citation needed|date=January 2016}} --> <!-- Please find a scientific paper that makes this statement before removing the tag -- and then the remark may be visible again --> When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen.<ref name=Fox>{{Cite news |last=Fox |first=Douglas |date=2007-03-28 |title=Primordial Soup's On: Scientists Repeat Evolution's Most Famous Experiment |periodical=Scientific American |series=History of Science |publisher=Scientific American Inc. |url=http://www.sciam.com/article.cfm?id=primordial-soup-urey-miller-evolution-experiment-repeated |accessdate=2008-07-09 }}<br>{{Cite journal | last1 = Cleaves | first1 = H. J. | last2 = Chalmers | first2 = J. H. | last3 = Lazcano | first3 = A. | last4 = Miller | first4 = S. L. | last5 = Bada | first5 = J. L. | title = A Reassessment of Prebiotic Organic Synthesis in Neutral Planetary Atmospheres | doi = 10.1007/s11084-007-9120-3 | journal = Origins of Life and Evolution of Biospheres | volume = 38 | issue = 2 | pages = 105–115 | year = 2008 | pmid = 18204914| bibcode = 2008OLEB...38..105C |url=http://www.astro.ulg.ac.be/~mouchet/BIOC0701-1/Cleaves-etal-2008.pdf |url-status=dead |archive-url=https://web.archive.org/web/20131107134729/http://www.astro.ulg.ac.be/~mouchet/BIOC0701-1/Cleaves-etal-2008.pdf |archive-date=2013-11-07 }}</ref>
|Isoserine
| 异丝氨酸
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==Earth's early atmosphere==
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Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, [[hydrogen sulfide]] (H<sub>2</sub>S), and [[sulfur dioxide]] (SO<sub>2</sub>) into the atmosphere.<ref name=Green>{{Cite journal|last=Green|first=Jack|title=Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife|journal=International Journal of Molecular Sciences|year=2011|volume=12|issue=9|pages=6051–6076|doi=10.3390/ijms12096051|pmid=22016644|pmc=3189768|ref=harv}}</ref> Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D [[enantiomer]]s) and experiments since have shown that "in the lab the two versions are equally likely to appear";<ref name="NS">{{Cite news |date=2006-06-02 |title=Right-handed amino acids were left behind |periodical=[[New Scientist]] |publisher=Reed Business Information Ltd |issue=2554 |pages=18 |url=https://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |accessdate=2008-07-09 |url-status=live |archiveurl=https://web.archive.org/web/20081024211531/http://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |archivedate=2008-10-24 }}</ref> however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.<ref>{{cite journal |last=Kojo |first=Shosuke |first2=Hiromi |last2=Uchino |first3=Mayu |last3=Yoshimura |first4=Kyoko |last4=Tanaka |date=October 2004 |title=Racemic D,L-asparagine causes enantiomeric excess of other coexisting racemic D,L-amino acids during recrystallization: a hypothesis accounting for the origin of L-amino acids in the biosphere |journal=Chemical Communications |volume= |issue=19 |pages=2146–2147 |pmid=15467844 |doi=10.1039/b409941a}}</ref>
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Originally it was thought that the primitive [[secondary atmosphere]] contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO<sub>2</sub> with perhaps some CO and the nitrogen mostly N<sub>2</sub>. In practice gas mixtures containing CO, CO<sub>2</sub>, N<sub>2</sub>, etc. give much the same products as those containing CH<sub>4</sub> and NH<sub>3</sub> so long as there is no O<sub>2</sub>. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, [[hydroxy acid|hydroxyacids]], purines, pyrimidines, and sugars have been made in variants of the Miller experiment.<ref name=bada2013/><ref>{{cite journal|last1=Ruiz-Mirazo|first1=Kepa|last2=Briones|first2=Carlos|last3=de la Escosura|first3=Andrés|title=Prebiotic Systems Chemistry: New Perspectives for the Origins of Life|journal=Chemical Reviews|year=2014|volume=114|issue=1|pages=285–366|doi=10.1021/cr2004844|pmid=24171674}}</ref>
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|α-Aminoisobutyric acid
|α-Aminoisobutyric acid
More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature.<ref>{{cite web |url=http://newsrelease.uwaterloo.ca/news.php?id=4348 |accessdate=2005-12-17 |title=Early Earth atmosphere favorable to life: study |publisher=University of Waterloo |url-status=dead |archiveurl=https://web.archive.org/web/20051214230357/http://newsrelease.uwaterloo.ca/news.php?id=4348 |archivedate=2005-12-14 }}</ref> One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.<ref>{{cite web |url=http://news-info.wustl.edu/news/page/normal/5513.html |accessdate=2005-12-17 |title=Calculations favor reducing atmosphere for early earth – Was Miller–Urey experiment correct? |first=Tony |last=Fitzpatrick |publisher=Washington University in St. Louis |year=2005 |url-status=dead |archiveurl=https://web.archive.org/web/20080720174657/http://news-info.wustl.edu/news/page/normal/5513.html |archivedate=2008-07-20 }}</ref>
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In contrast to the general notion of early earth's reducing atmosphere, researchers at the [[Rensselaer Polytechnic Institute]] in New York reported the possibility of oxygen available around 4.3 billion years ago. Their study reported in 2011 on the assessment of Hadean [[zircons]] from the earth's interior ([[magma]]) indicated the presence of oxygen traces similar to modern-day lavas.<ref>{{cite journal|last1=Trail|first1=Dustin|last2=Watson|first2=E. Bruce|last3=Tailby|first3=Nicholas D.|title=The oxidation state of Hadean magmas and implications for early Earth's atmosphere|journal=Nature|year=2011|volume=480|issue=7375|pages=79–82|doi=10.1038/nature10655|pmid=22129728|bibcode=2011Natur.480...79T|url=https://www.semanticscholar.org/paper/e87ff5db353f56ac40649b2a4ca618f3c2067cdb}}</ref> This study suggests that oxygen could have been released in the earth's atmosphere earlier than generally believed.<ref>{{cite journal|last1=Scaillet|first1=Bruno|last2=Gaillard|first2=Fabrice|title=Earth science: Redox state of early magmas|journal=Nature|date=2011|volume=480|issue=7375|pages=48–49|doi=10.1038/480048a|pmid=22129723|bibcode=2011Natur.480...48S|url=https://hal.archives-ouvertes.fr/file/index/docid/648930/filename/Scaillet-Nature2-2011.pdf|url-status=live|archiveurl=https://web.archive.org/web/20171026110646/https://hal.archives-ouvertes.fr/file/index/docid/648930/filename/Scaillet-Nature2-2011.pdf|archivedate=2017-10-26|citeseerx=10.1.1.659.2086}}</ref>
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==Extraterrestrial sources==
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Conditions similar to those of the Miller–Urey experiments are present in other regions of the [[solar system]], often substituting [[ultraviolet]] light for lightning as the energy source for chemical reactions.<ref>{{cite journal|last1=Nunn|first1=JF|title=Evolution of the atmosphere|journal=Proceedings of the Geologists' Association. Geologists' Association|year=1998|volume=109|issue=1|pages=1–13|pmid=11543127|doi=10.1016/s0016-7878(98)80001-1}}</ref><ref>{{cite journal|last1=Raulin|first1=F|last2=Bossard|first2=A|title=Organic syntheses in gas phase and chemical evolution in planetary atmospheres.|journal=Advances in Space Research|year=1984|volume=4|issue=12|pages=75–82|pmid=11537798|doi=10.1016/0273-1177(84)90547-7|bibcode=1984AdSpR...4...75R}}</ref><ref>{{cite journal|last1=Raulin|first1=François|last2=Brassé|first2=Coralie|last3=Poch|first3=Olivier|last4=Coll|first4=Patrice|title=Prebiotic-like chemistry on Titan|journal= Chemical Society Reviews|year=2012|volume=41|issue=16|pages=5380–93|doi=10.1039/c2cs35014a|pmid=22481630}}</ref> The [[Murchison meteorite]] that fell near [[Murchison, Victoria]], Australia in 1969 was found to contain over 90 different amino acids, nineteen of which are found in Earth life. [[Comet]]s and other [[Trans-Neptunian object|icy outer-solar-system bodies]] are thought to contain large amounts of complex carbon compounds (such as [[tholin]]s) formed by these processes, darkening surfaces of these bodies.<ref>{{cite journal |vauthors=Thompson WR, Murray BG, Khare BN, Sagan C |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: applications to the outer solar system |journal=Journal of Geophysical Research |volume=92 |issue=A13 |pages=14933–47 |date=December 1987 |pmid=11542127 |doi=10.1029/JA092iA13p14933 |bibcode=1987JGR....9214933T|title-link=methane clathrate }}</ref> The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed.<ref>{{cite journal|last=PIERAZZO|first=E.|author2=CHYBA C.F.|title=Amino acid survival in large cometary impacts|journal=Meteoritics & Planetary Science|year=2010|volume=34|issue=6|pages=909–918|doi=10.1111/j.1945-5100.1999.tb01409.x|bibcode=1999M&PS...34..909P}}</ref> This has been used to infer an origin of life outside of Earth: the [[panspermia]] hypothesis.
|β-Aminoisobutyric acid
|β-Aminoisobutyric acid
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==Recent related studies==
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In recent years, studies have been made of the [[amino acid]] composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated [[species]], assumed to share only the [[last universal ancestor]] (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.<ref>{{cite journal |author1=Brooks D.J. |author2=Fresco J.R. |author3=Lesk A.M. |author4=Singh M. |url=http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |title=Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code |journal=Molecular Biology and Evolution |date=October 1, 2002 |volume=19 |pages=1645–55 |pmid=12270892 |issue=10 |doi=10.1093/oxfordjournals.molbev.a003988 |url-status=dead |archiveurl=https://web.archive.org/web/20041213094516/http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |archivedate=December 13, 2004 |doi-access=free }}</ref>
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[[Jeffrey Bada]], himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.<ref name="BBC">{{cite web |website=BBC Four |url=http://www.bbc.co.uk/programmes/b00mbvfh |title=The Spark of Life |url-status=live |archive-url=https://web.archive.org/web/20101113011054/http://www.bbc.co.uk/programmes/b00mbvfh |archive-date=2010-11-13 |postscript=. TV Documentary. |date=26 August 2009}}</ref>
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|β-Aminobutyric acid
|β-Aminobutyric acid
In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of [[Charles Darwin]]'s envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of [[volcano|volcanic]] eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using [[high-performance liquid chromatography]] and [[mass spectrometry]], the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 [[amine]]s and many [[hydroxylate]]d molecules, which could have been formed by [[hydroxyl radical]]s produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of [[carbonyl sulfide]] there could have helped these molecules form [[peptide]]s.<ref name=Johnson2008>{{cite journal |vauthors=Johnson AP, Cleaves HJ, Dworkin JP, Glavin DP, Lazcano A, Bada JL |title=The Miller volcanic spark discharge experiment |journal=Science |volume=322 |issue=5900 |pages=404 |date=October 2008 |pmid=18927386 |doi=10.1126/science.1161527|bibcode = 2008Sci...322..404J }}</ref><ref>{{cite web | title='Lost' Miller–Urey Experiment Created More Of Life's Building Blocks | date=October 17, 2008 | website=Science Daily | url=https://www.sciencedaily.com/releases/2008/10/081016141411.htm | accessdate=2008-10-18 | url-status=live | archiveurl=https://web.archive.org/web/20081019111114/http://www.sciencedaily.com/releases/2008/10/081016141411.htm | archivedate=October 19, 2008 }}</ref>
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The main problem of theories based around [[amino acids]] is the difficulty in obtaining spontaneous formation of peptides. Since [[John Desmond Bernal]]'s suggestion that clay surfaces could have played a role in [[abiogenesis]]<ref name=Bernal1949>{{cite journal |vauthors=Bernal JD |title=The physical basis of life |journal=Proc. Phys. Soc. A | issue=9 |volume=62 |pages=537–558 |date=1949|doi=10.1088/0370-1298/62/9/301 |bibcode=1949PPSA...62..537B }}</ref>, scientific efforts have been dedicated to investigating clay-mediated [[peptide bond]] formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators <ref name="RT-2018">{{cite news | publisher=RT | url=https://www.rt.com/news/416581-scientists-unlock-life-puzzle-protein/ | title='How did life form from rocks?' Protein puzzle reveals secrets of Earth's evolution | date=January 2017}}</ref><ref name="Erastova2017">{{cite journal |vauthors=Erastova V, Degiacomi MT, Fraser D, Greenwell HC |title=Mineral surface chemistry control for origin of prebiotic peptides |journal=Nature Communications |volume=8 |issue=1 |pages=2033 |date=December 2017|pmid=29229963 |pmc=5725419 |doi=10.1038/s41467-017-02248-y |bibcode=2017NatCo...8.2033E }}</ref> suggested that peptides could form at the interlayers of [[layered double hydroxides]] such as [[green rust]] in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a [[ribosome]]-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.
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In October 2018, researchers at [[McMaster University]] on behalf of the [[Origins Institute]] announced the development of a new technology, called a ''[[Planet Simulator]]'', to help study the [[origin of life]] on planet [[Earth]] and beyond.<ref name="BW-20181004">{{cite news |last=Balch |first=Erica |title=Ground-breaking lab poised to unlock the mystery of the origins of life on Earth and beyond |url=https://brighterworld.mcmaster.ca/articles/ground-breaking-lab-poised-to-unlock-the-mystery-of-the-origins-of-life-on-earth-and-beyond/ |date=4 October 2018 |work=[[McMaster University]] |accessdate=4 October 2018 }}</ref><ref name="EA-20181004">{{cite news |author=Staff |title=Ground-breaking lab poised to unlock the mystery of the origins of life |url=https://www.eurekalert.org/pub_releases/2018-10/mu-glp100418.php |date=4 October 2018 |work=[[EurekAlert!]] |accessdate=14 October 2018 }}</ref><ref name="IVG-2018">{{cite web |author=Staff |title=Planet Simulator |url=https://www.intravisiongroup.com/planet-simulator |date=2018 |work=IntraVisionGroup.com |accessdate=14 October 2018 }}</ref><ref name="ES-209181014">{{cite web |last=Anderson |first=Paul Scott |title=New technology may help solve mystery of life's origins - How did life on Earth begin? A new technology, called Planet Simulator, might finally help solve the mystery. |url=http://earthsky.org/space/new-technology-solve-mystery-of-lifes-origins |date=14 October 2018 |work=[[EarthSky]] |accessdate=14 October 2018 }}</ref>
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|γ-Aminobutyric acid
|γ-Aminobutyric acid
==Amino acids identified==
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{{Category see also|Chemical synthesis of amino acids}}
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Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as published by Miller in 1953,<ref name=miller1953/> the 2008 re-analysis of vials from the volcanic spark discharge experiment,<ref>{{cite web|last1=Myers|first1=P. Z.|title=Old scientists never clean out their refrigerators|url=http://scienceblogs.com/pharyngula/2008/10/old_scientists_never_clean_out.php|website=Pharyngula|accessdate=7 April 2016|archiveurl=https://web.archive.org/web/20081017231050/http://scienceblogs.com/pharyngula/2008/10/old_scientists_never_clean_out.php|archivedate=October 17, 2008|date=October 16, 2008}}</ref> and the 2010 re-analysis of vials from the H<sub>2</sub>S-rich spark discharge experiment.<ref>{{cite journal|title=Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment|journal=Proceedings of the National Academy of Sciences|date=February 14, 2011|volume=108|issue=14|doi=10.1073/pnas.1019191108|pmid=21422282|pmc=3078417|pages=5526–31|last1=Parker|first1=ET|last2=Cleaves|first2=HJ|last3=Dworkin|first3=JP|display-authors=etal |bibcode=2011PNAS..108.5526P|df=}}</ref>
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{|class="wikitable sortable" style="text-align:right"
|Valine
瓦林
|-
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! scope="col" rowspan="2" | Amino acid
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! scope="col" colspan="3" | Produced in experiment
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! scope="col" rowspan="2" | [[Proteinogenic]]
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|-
|-
! scope="col" | Miller–Urey<br/>{{small|(1952)}}
|Isovaline
异缬氨酸
! scope="col" | Volcanic spark discharge<br/>{{small|(2008)}}
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|
! scope="col" | H<sub>2</sub>S-rich spark discharge<br/>{{small|(2010)}}
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|-
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|[[Glycine]]
|
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| {{ya}}
|-
|-
| {{ya}}
|Glutamic acid
谷氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[alanine|α-Alanine]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|Norvaline
诺瓦林
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[beta-Alanine|β-Alanine]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|α-Aminoadipic acid
Α-氨基己二酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
|
|[[Aspartic acid]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|Homoserine
高丝氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
|
|[[alpha-Aminobutyric acid|α-Aminobutyric acid]]
|
|
| {{ya}}
|-
|-
| {{ya}}
|2-Methylserine
| 2- 甲基丝氨酸
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Serine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|β-Hydroxyaspartic acid
|β-Hydroxyaspartic acid
| {{ya}}
|
|
| {{yes}}
|
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|-
|
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|[[Isoserine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Ornithine
鸟氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
|
|[[2-Aminoisobutyric acid|α-Aminoisobutyric acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|2-Methylglutamic acid
| 2- 甲基谷氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
|
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|[[3-Aminoisobutyric acid|β-Aminoisobutyric acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Phenylalanine
| 苯丙氨酸
| {{ya}}
|
|
| {{no}}
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|-
|
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|[[beta-Aminobutyric acid|β-Aminobutyric acid]]
|
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| {{na}}
|-
|-
| {{ya}}
|Homocysteic acid
高同型半胱氨酸
| {{ya}}
|
|
| {{no}}
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|-
|
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|[[gamma-Aminobutyric acid|γ-Aminobutyric acid]]
|
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| {{na}}
|-
|-
| {{ya}}
|S-Methylcysteine
S- 甲基半胱氨酸
| {{ya}}
|
|
| {{no}}
|
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|-
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|[[Valine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Methionine
| 蛋氨酸
| {{ya}}
|
|
| {{yes}}
|
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|-
|
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|[[Isovaline]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Methionine sulfoxide
蛋氨酸亚砜
| {{ya}}
|
|
| {{no}}
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|-
|
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|[[Glutamic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Methionine sulfone
蛋氨酸砜
| {{ya}}
|
|
| {{yes}}
|
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|-
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|[[Norvaline]]
|
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| {{na}}
|-
|-
| {{ya}}
|Isoleucine
异亮氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
|
|[[alpha-Aminoadipic acid|α-Aminoadipic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Leucine
亮氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[Homoserine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Ethionine
|Ethionine
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[2-Methylserine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Cysteine
半胱氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
|
|[[3-Hydroxyaspartic acid|β-Hydroxyaspartic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Histidine
| 组氨酸
| {{na}}
|
|
| {{no}}
|
|
|-
|
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|[[Ornithine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Lysine
赖氨酸
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[2-Methylglutamic acid]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Asparagine
天冬酰胺
| {{na}}
|
|
| {{no}}
|
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|-
|
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|[[Phenylalanine]]
|
|
| {{na}}
|-
|-
| {{ya}}
|Pyrrolysine
| 吡咯赖氨酸
| {{na}}
|
|
| {{yes}}
|
|
|-
|
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|[[Homocysteic acid]]
|
|
| {{na}}
|-
|-
| {{na}}
|Proline
| Proline
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[S-methylcysteine|''S''-Methylcysteine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Glutamine
谷氨酰胺
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Methionine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Arginine
精氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Methionine sulfoxide]]
|
|
| {{na}}
|-
|-
| {{na}}
|Threonine
苏氨酸
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Methionine sulfone]]
|
|
| {{na}}
|-
|-
| {{na}}
|Selenocysteine
硒代半胱氨酸
| {{ya}}
|
|
| {{no}}
|
|
|-
|
|
|[[Isoleucine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Tryptophan
色氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Leucine]]
|
|
| {{na}}
|-
|-
| {{na}}
|Tyrosine
| 酪氨酸
| {{ya}}
|
|
| {{yes}}
|
|
|-
|
|
|[[Ethionine]]
|
|
| {{na}}
|}
|}
| {{na}}
| {{ya}}
| {{no}}
|-
|[[Cysteine]]
| {{na}}
| {{na}}
| {{na}}
| {{yes}}
|-
|[[Histidine]]
| {{na}}
| {{na}}
| {{na}}
| {{yes}}
|-
|[[Lysine]]
| {{na}}
| {{na}}
Category:Articles containing video clips
类别: 包含视频剪辑的文章
| {{na}}
Category:Biology experiments
类别: 生物学实验
| {{yes}}
Category:Chemical synthesis of amino acids
类别: 氨基酸的化学合成
|-
Category:Chemistry experiments
类别: 化学实验
|[[Asparagine]]
Category:Origin of life
类别: 生命的起源
| {{na}}
Category:1952 in biology
分类: 1952年生物学
| {{na}}
Category:1953 in biology
分类: 1953年生物学
| {{na}}
Category:2008 in science
分类: 2008年科学
<noinclude>
<small>This page was moved from [[wikipedia:en:Miller–Urey experiment]]. Its edit history can be viewed at [[米勒-尤里实验/edithistory]]</small></noinclude>
[[Category:待整理页面]]