Spiegelman Monster is the name given to an RNA chain of only 218 nucleotides that is able to be reproduced by an RNA replication enzyme. It is named after its creator, Sol Spiegelman, of the University of Illinois at Urbana-Champaign.
Spiegelman introduced RNA from a simple Bacteriophage Qβ (Qβ) into a solution which contained the RNA replication enzyme RNA replicase from the Qβ virus Q-Beta Replicase, some free nucleotides and some salts. In this environment, the RNA started to replicate.[1] After a while, Spiegelman took some RNA and moved it to another tube with fresh solution. This process was repeated.[2]
Shorter RNA chains were able to replicate 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. Such a short RNA had been able to replicate very quickly in these unnatural circumstances.
In 1997, Eigen and Oehlenschlager showed that the Spiegelman monster eventually becomes even shorter, containing only 48 or 54 nucleotides, which are simply the binding sites for the reproducing enzyme RNA replicase.[3]
M. Sumper and R. Luce of Eigen's laboratory demonstrated that a mixture containing no RNA at all but only RNA bases and Q-Beta Replicase can, under the right conditions, spontaneously generate self-replicating RNA which evolves into a form similar to Spiegelman's Monster.[4]