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A Hypothetical Pathway from the NRA to the DNA World


Line, MA, A Hypothetical Pathway from the NRA to the DNA World, Origins of Life and Evolution of Biospheres, 35, (4) pp. 395-400. ISSN 0169-6149 (2005) [Refereed Article]

DOI: doi:10.1007/s11084-005-2043-y


If the DNA world was preceded by a RNA world as widely suggested a rational pathway should be discernable to link the two. This report uses as a starting point a membrane-enclosed ribozyme capable of polymerising itself and its counterpart copy. As molecular complexity increased, it is suggested that a consortia of the initial ribozyme polymerase and chaperone molecules formed a complex specifically for RNA replication. A mutation in one of several copy-genomes coding for these replication machines then led in step-wise fashion to a proto-ribosome that increasingly inserted specific amino acids instead of nucleotides into a growing RNA chain, the driving force being selection for improved or new function. Eventually the nucleotides would be entirely displaced in this proto-ribosome, after which the ribose-phosphate linkage would be replaced by peptide linkage. The final steps would be the formation of DNA from the RNA genomic material viareverse transcriptase, coupled with the evolution of enzymes for DNA polymerisation and transcription. At this point the original RNA-replicator machinery would be redundant and eliminated, the RNA genomic material would become mRNA and the present-day function of the ribosome would be fixed. In the scenario described a mechanism for the selection for L-amino acids becomes evident. © Springer 2005.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Microbiology not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Line, MA (Dr Martin Line)
ID Code:29328
Year Published:2005
Web of Science® Times Cited:3
Deposited By:Agricultural Science
Deposited On:2005-08-01
Last Modified:2006-05-03

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