The idea was to simulate hypothetical conditions thought to be present on the early Earth (Hadean or early Archaean). It was a test of the chemical origins of life. Specifically, the experiment tested Alexander Oparin's and J.B.S. Haldane's hypothesis that conditions on the primitive Earth favored chemical reactions that synthesized organic compounds from inorganic precursors. Considered to be the classic experiment on the origin of life, it was conducted in 1952 and published in 1953 by Stanley Miller and Harold Urey at the University of Chicago.
After Miller's death in 2007, scientists examined sealed vials preserved from the original experiments. They were able to show that there were well over 20 different amino acids produced in Miller's original experiments. That is considerably more than those Miller originally reported, and more than the 20 that naturally occur in life.
[change | change source]
Moreover, some evidence suggests that Earth's original atmosphere might have had a different composition than the gas used in 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 (H2S), and sulfur dioxide (SO2) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules.
Note that organic compounds, including amino acids, are present in the meteorite dust which rains down on Earth. Therefore, interest in abiogenesis and the origin of life has shifted to the question of how cells and large macromolecules formed.
References[change | change source]
- Hill H.G. & Nuth J.A. (2003). "The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems". Astrobiology 3 (2): 291–304. doi:10.1089/153110703769016389. PMID 14577878.
- Balm S.P; Hare J.P. & Kroto H.W. (1991). "The analysis of comet mass spectrometric data". Space Science Reviews 56: 185–9. doi:10.1007/BF00178408.
- Miller, Stanley L. (1953). "Production of amino acids under possible primitive Earth conditions" (PDF). Science 117 (3046): 528. doi:10.1126/science.117.3046.528. PMID 13056598. http://www.abenteuer-universum.de/pdf/miller_1953.pdf.
- Miller, Stanley L.; Harold C. Urey (1959). "Organic ccompound synthesis on the primitive Earth". Science 130 (3370): 245. doi:10.1126/science.130.3370.245. PMID 13668555. Miller states that he made "A more complete analysis of the products" in the 1953 experiment, listing additional results.
- A. Lazcano, J.L. Bada (2004). "The 1953 Stanley L. Miller experiment: fifty years of prebiotic organic chemistry". Origins of Life and Evolution of Biospheres 33 (3): 235–242. doi:10.1023/A:1024807125069. PMID 14515862.
- Bada, Jeffrey L. (2000). "Stanley Miller's 70th Birthday". Origins of life and evolution of the biosphere (Netherlands: Kluwer) 30: 107–12.
- BBC: The spark of life. TV documentary, BBC 4, 26 August 2009.
- "Right-handed amino acids were left behind". New Scientist (Reed Business Information Ltd) (2554): pp. 18. 2006-06-02. http://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html. Retrieved 2008-07-09.
- Brooks D.J. et al (2002). "Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code". Molecular Biology and Evolution 19 (10): 1645–55. PMID 12270892. http://mbe.oupjournals.org/cgi/content/full/19/10/1645.