Spiegelman's Monster is the name given to an
RNA
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
chain of only 218
nucleotides
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules w ...
that is able to be reproduced by the RNA replication enzyme
RNA-dependent RNA polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to t ...
, also called RNA replicase. It is named after its creator,
Sol Spiegelman
Sol Spiegelman (December 14, 1914 – January 21, 1983) was an American molecular biologist. He developed the technique of nucleic acid hybridization, which helped to lay the groundwork for advances in recombinant DNA technology.
Early life and ...
, of the
University of Illinois at Urbana-Champaign
The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the Univ ...
who first described it in 1965.
Description
Spiegelman introduced RNA from a simple
bacteriophage Qβ
Bacteriophage Qbeta (''Qubevirus durum''), commonly referred to as Qbeta or Qβ, is a positive-strand RNA virus which infects bacteria that have F-pili, most commonly ''Escherichia coli''. Its linear genome is packaged into an icosahedral capsid ...
(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.
Further work
M. Sumper and R. Luce of
Manfred Eigen
Manfred Eigen (; 9 May 1927 – 6 February 2019) was a German Biophysical chemistry, biophysical chemist who won the 1967 Nobel Prize in Chemistry for work on measuring fast chemical reactions.
Eigen's research helped solve major problems in ...
'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. However, Chetverin and colleagues later showed that the 'spontaneous' RNA generation was due to
environmental RNA contamination.
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
A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, ...
and
T7 RNA polymerase
T7 RNA Polymerase is an RNA polymerase from the T7 bacteriophage that catalyzes the formation of RNA from DNA in the 5'→ 3' direction.
Activity
T7 polymerase is extremely promoter-specific and transcribes only DNA downstream of a T7 promot ...
.
See also
*
Abiogenesis
In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothes ...
*
RNA world hypothesis
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence ...
*
PAH world hypothesis
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, including in comets, and assumed to be abundant in the primordial soup of the early Earth, played ...
*
Viroid
Viroids are small single-stranded, circular RNAs that are infectious pathogens. Unlike viruses, they have no protein coating. All known viroids are inhabitants of angiosperms (flowering plants), and most cause diseases, whose respective economi ...
References
External links
ASA - January 2000: almost life
{{Organisms et al.
Origin of life
RNA
Molecular evolution