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第232行： − + − 近年来，人们对“老”基因中“老”区域的产物的氨基酸组成进行了研究，“老”基因被定义为来自几个相距甚远的物种的生物体所共有的氨基酸组成，这些物种被认为在所有现存物种中只共享最后共同祖先。这些研究发现，这些区域的产物富含那些在 Miller-Urey 实验中也最容易产生的氨基酸。这表明，最初的遗传密码是基于比现在更少的氨基酸-只有那些在益生元性质-比目前的。+ −
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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>
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>
最近的研究结果可能会质疑这些结论。滑铁卢大学和科罗拉多大学在2005年进行了模拟，结果表明地球早期大气中可能含有高达40%的氢，这意味着有利于形成益生元有机分子的环境更加有利。氢从地球大气层逃逸到太空的速度可能只有先前根据对高层大气温度的修正估计而认为的速率的百分之一。[24]作者之一欧文·图恩指出：“在这种新的情况下，早期大气中可以有效地产生有机物，带我们回到海洋中有机丰富的汤的概念。】我认为这项研究使米勒和其他人的实验再次具有相关性。“利用早期地球的球粒陨石模型进行放气计算，补充了滑铁卢/科罗拉多州的结果，重新确立了米勒-尤里实验的重要性
最近的研究结果可能会质疑这些结论。滑铁卢大学和科罗拉多大学在2005年进行了模拟，结果表明地球早期大气中可能含有高达40%的氢，这意味着有利于形成益生元有机分子的环境更加有利。氢从地球大气层逃逸到太空的速度可能只有先前根据对高层大气温度的修正估计而认为的速率的百分之一。[24]作者之一欧文·图恩指出：“在这种新的情况下，早期大气中可以有效地产生有机物，带我们回到海洋中有机丰富的汤的概念。我认为这项研究使米勒和其他人的实验再次具有相关性。“利用早期地球的球粒陨石模型进行放气计算，补充了滑铁卢/科罗拉多州的结果，重新确立了米勒-尤里实验的重要性
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>
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>
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.
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.
与米勒-乌雷实验相似的条件也存在于太阳系的其他区域，通常用紫外线代替闪电作为化学反应的能源。1969年落在澳大利亚维多利亚州默奇森附近的莫奇森陨石被发现含有90多种不同的氨基酸，地球上有19个生命。彗星和其他冰冷的太阳系外天体被认为含有大量由这些过程形成的复杂碳化合物（如索林类化合物），使这些天体的表面变暗。早期地球受到彗星的猛烈轰炸，可能与水和其他挥发物一起提供了大量复杂的有机分子他们对此作出了贡献。这被用来推断地球外生命的起源：胚种假说。
与米勒-尤里实验相似的条件也存在于太阳系的其他区域，通常用紫外线代替闪电作为化学反应的能源。1969年落在澳大利亚维多利亚州默奇森附近的莫奇森陨石被发现含有90多种不同的氨基酸，地球上有19个生命。彗星和其他冰冷的太阳系外天体被认为含有大量由这些过程形成的复杂碳化合物（如索林类化合物），使这些天体的表面变暗。早期地球受到彗星的猛烈轰炸，可能与水和其他挥发物一起提供了大量复杂的有机分子他们对此作出了贡献。这被用来推断地球外生命的起源：胚种假说。
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.
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.
近年来，人们对“老”基因中“老”区域产物的氨基酸组成进行了研究，这些“老”基因被定义为是几种广泛分离的物种的有机体所共有的氨基酸成分，假设它们只共享所有现存物种的最后一个宇宙祖先（LUA）。这些研究发现，这些区域的产物富含那些在 Miller-Urey 实验中也最容易产生的氨基酸。这表明，最初的遗传密码是基于比现在更少的氨基酸-只有那些具有益生元性质的氨基酸
==Recent related studies近年相关研究==
==Recent related studies近年相关研究==