Book contents
- Frontmatter
- Contents
- Contributors
- THE MOLECULAR ORIGINS OF LIFE CAMBRIDGE
- Introduction
- Part I Setting the stage
- Part II Organic molecules on the early Earth
- Part III Possible starts for primitive life
- 8 Membrane compartments in prebiotic evolution
- 9 Origin of life in an iron–sulfur world
- 10 Clues from present-day biology: the thioester world
- 11 Origins of the RNA world
- 12 Catalyzed RNA synthesis for the RNA world
- 13 Catalysis in the RNA world
- 14 Self-replication and autocatalysis
- Part IV Clues from the bacterial world
- Part V Clues from other planets
- Conclusion
- Index
11 - Origins of the RNA world
Published online by Cambridge University Press: 06 January 2010
- Frontmatter
- Contents
- Contributors
- THE MOLECULAR ORIGINS OF LIFE CAMBRIDGE
- Introduction
- Part I Setting the stage
- Part II Organic molecules on the early Earth
- Part III Possible starts for primitive life
- 8 Membrane compartments in prebiotic evolution
- 9 Origin of life in an iron–sulfur world
- 10 Clues from present-day biology: the thioester world
- 11 Origins of the RNA world
- 12 Catalyzed RNA synthesis for the RNA world
- 13 Catalysis in the RNA world
- 14 Self-replication and autocatalysis
- Part IV Clues from the bacterial world
- Part V Clues from other planets
- Conclusion
- Index
Summary
A paradigm for the origin of life
The theory that life began in an “RNA world” postulates that the first chemical system to appear on Earth with the capability to replicate itself was a set of RNA molecules. Replication of sequence information is an implicit and critical concept here, rather than mere “reproduction,” since only a system that quite faithfully reproduces the properties of its parents is capable of Darwinian evolution. The arguments in favor of the theory that life originated with RNA are both chemical and biological in nature (Joyce 1989). The chemical properties that support such a potential will be considered briefly later in connection with the template-directed oligomerization of mononucleotides. The central role of RNA in the expression of genetic information is probably the most persuasive of the biological lines of evidence. The most impressive demonstration of the evolutionary potential of RNA is the fact that selection experiments reveal a growing catalogue of new catalytic functions of RNA molecules (see Chapter 13). Once self-replicating RNA molecules appear on the scene, it becomes possible to understand how evolution could produce increasingly efficient self-replicating systems, although the origin of encoded protein synthesis still presents serious theoretical difficulties. However, the task set for this chapter is to look backward from RNA and ask how the RNA world got its start.
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- The Molecular Origins of LifeAssembling Pieces of the Puzzle, pp. 237 - 254Publisher: Cambridge University PressPrint publication year: 1998
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