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.
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. After a while, Spiegelman took some RNA and moved it to another tube with fresh solution. This process was repeated.
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 demonstrated that a mixture containing no RNA at all but only RNA bases and Qβ replicase can, under the right conditions, spontaneously generate self-replicating RNA which evolves into a form similar to Spiegelman's Monster. Note that despite the term self-replicating RNA, the RNA did not replicate itself: the Qβ enzyme is what made the RNA molecules.
- 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. doi:10.1073/pnas.54.3.919. PMC 219765. PMID 5217468.CS1 maint: Multiple names: authors list (link)
- 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. doi:10.1073/pnas.58.1.217. PMC 335620. PMID 5231602.CS1 maint: Multiple names: authors list (link)
- 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. doi:10.1073/pnas.69.10.3038. PMC 389702. PMID 4507621.CS1 maint: Multiple names: authors list (link)
- 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. doi:10.1073/pnas.72.1.162. PMC 432262. PMID 1054493.