Per citar aquest document: http://ddd.uab.cat/record/113190
Evolution before genes
Vasas, Vera (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Fernando, Chrisantha (University of London. School of Electronic Engineering and Computer Science)
Santos, Mauro (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Kauffman, Stuart (University of Calgary. Institute for Biocomplexity and Informatics)
Szathmáry, Eörs (Eötvös University. Institute of Biology (Budapest, Hongria))

Data: 2012
Resum: Background: Our current understanding of evolution is so tightly linked to template-dependent replication of DNA and RNA molecules that the old idea from Oparin of a self-reproducing 'garbage bag' ('coacervate') of chemicals that predated fully-fledged cell-like entities seems to be farfetched to most scientists today. However, this is exactly the kind of scheme we propose for how Darwinian evolution could have occurred prior to template replication. Results: We cannot confirm previous claims that autocatalytic sets of organic polymer molecules could undergo evolution in any interesting sense by themselves. While we and others have previously imagined inhibition would result in selectability, we found that it produced multiple attractors in an autocatalytic set that cannot be selected for. Instead, we discovered that if general conditions are satisfied, the accumulation of adaptations in chemical reaction networks can occur. These conditions are the existence of rare reactions producing viable cores (analogous to a genotype), that sustains a molecular periphery (analogous to a phenotype). Conclusions: We conclude that only when a chemical reaction network consists of many such viable cores, can it be evolvable. When many cores are enclosed in a compartment there is competition between cores within the same compartment, and when there are many compartments, there is between-compartment competition due to the phenotypic effects of cores and their periphery at the compartment level. Acquisition of cores by rare chemical events, and loss of cores at division, allows macromutation, limited heredity and selectability, thus explaining how a poor man's natural selection could have operated prior to genetic templates. This is the only demonstration to date of a mechanism by which pre-template accumulation of adaptation could occur.
Drets: Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades. Creative Commons
Llengua: Anglès
Document: article ; publishedVersion
Publicat a: Biology direct, Vol. 7, Núm. 1 (January 2012) , p. 1-14, ISSN 1745-6150

DOI: 10.1186/1745-6150-7-1


14 p, 801.8 KB

Additional file 1
24 p, 496.5 KB

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