Spiegelman's Monster

Spiegelman's Monster is the name given to an RNA chain of only 218 nucleotides that is able to be reproduced by the RNA replication enzyme RNA-dependent RNA polymerase, also called RNA replicase. It is named after its creator, Sol Spiegelman, of the University of Illinois at Urbana-Champaign who first described it in 1965.

Description

Spiegelman introduced RNA from a simple bacteriophage Qβ (Qβ) into a solution which contained Qβ's RNA replicase, some free nucleotides, and some salts. In this environment, the RNA started to be replicated.[1][2] After a while, Spiegelman took some RNA and moved it to another tube with fresh solution. This process was repeated.[3]

Shorter RNA chains were able to be replicated faster, so the RNA became shorter and shorter as selection favored speed. After 74 generations, the original strand with 4,500 nucleotide bases ended up as a dwarf genome with only 218 bases. This short RNA sequence replicated very quickly in these unnatural circumstances.

M. Sumper and R. Luce of Eigen's laboratory replicated the experiment, except without adding RNA, only RNA bases and Qβ replicase. They found that under the right conditions the Qβ replicase can spontaneously generate RNA which evolves into a form similar to Spiegelman's Monster.[4] However, Chetverin and colleagues later showed that the 'spontaneous' RNA generation was due to environmental RNA contamination.[5] Eigen built on Spiegelman's work and produced a similar system further degraded to just 48 or 54 nucleotides—the minimum required for the binding of the replication enzyme, this time a combination of HIV-1 reverse transcriptase and T7 RNA polymerase.[6][7]

See also

References
  1. Spiegelman, S., Haruna, I., Holland, I.B., Beaudreau, G. & Mills, D. (1965). "The Synthesis of a Self-propagating and Infectious Nucleic Acid with a Purified Enzyme". Proc. Natl. Acad. Sci. USA. 54 (3): 919–927. Bibcode:1965PNAS...54..919S. doi:10.1073/pnas.54.3.919. PMC 219765. PMID 5217468.CS1 maint: multiple names: authors list (link)
  2. Mills, D. R., R. L. Peterson, Sol Spiegelman (1967). "An extracellular Darwinian experiment with a self-duplicating nucleic acid molecule". Proceedings of the National Academy of Sciences. 58 (1): 217–24. Bibcode:1967PNAS...58..217M. doi:10.1073/pnas.58.1.217. PMC 335620. PMID 5231602.CS1 maint: multiple names: authors list (link)
  3. Kacian,D.L., D.R. Mills, F.R. Kramer, S. Spiegelman (1972). "A Replicating RNA Molecule Suitable for a Detailed Analysis of Extracellular Evolution and Replication". Proceedings of the National Academy of Sciences. 69 (10): 3038–3042. Bibcode:1972PNAS...69.3038K. doi:10.1073/pnas.69.10.3038. PMC 389702. PMID 4507621.CS1 maint: multiple names: authors list (link)
  4. Sumper, M; R. Luce (1975). "Evidence for de novo production of self-replicating and environmentally adapted RNA structures by bacteriophage Qbeta replicase" (PDF). Proceedings of the National Academy of Sciences. 72 (1): 162–166. Bibcode:1975PNAS...72..162S. doi:10.1073/pnas.72.1.162. PMC 432262. PMID 1054493.
  5. Chetverina, H. V.; Demidenko, A. A.; Ugarov, V. I.; Chetverin, A. B. (1999-04-30). "Spontaneous rearrangements in RNA sequences". FEBS Letters. 450 (1–2): 89–94. doi:10.1016/S0014-5793(99)00469-X. ISSN 0014-5793. PMID 10350063.
  6. Oehlenschläger, Frank; Eigen, Manfred (December 1997). "30 Years Later – a New Approach to Sol Spiegelman's and Leslie Orgel's in vitro Evolutionary Studies Dedicated to Leslie Orgel on the occasion of his 70th birthday". Origins of Life and Evolution of Biospheres. 27 (5–6): 437–457. Bibcode:1997OLEB...27..437O. doi:10.1023/A:1006501326129. PMID 9394469.
  7. Dawkins, Richard; Wong, Yan (2016). The Ancestor's Tale. ISBN 978-0544859937.
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