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Evolutionary Constraints to Viroid Evolution
Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Campus UPV CPI access G, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
* Author to whom correspondence should be addressed.
Received: 10 July 2009; in revised form: 27 August 2009 / Accepted: 27 August 2009 / Published: 2 September 2009
Abstract: We suggest that viroids are trapped into adaptive peaks as the result of adaptive constraints. The first one is imposed by the necessity to fold into packed structures to escape from RNA silencing. This creates antagonistic epistases, which make future adaptive trajectories contingent upon the first mutation and slow down the rate of adaptation. This second constraint can only be surpassed by increasing genetic redundancy or by recombination. Eigen’s paradox imposes a limit to the increase in genome complexity in the absence of mechanisms reducing mutation rate. Therefore, recombination appears as the only possible route to evolutionary innovation in viroids.
Keywords: epistasis; evolutionary constraints; genome complexity; mutation rate; RNA folding; viroid evolution
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Elena, S.F.; Gómez, G.; Daròs, J.-A. Evolutionary Constraints to Viroid Evolution. Viruses 2009, 1, 241-254.
Elena SF, Gómez G, Daròs J-A. Evolutionary Constraints to Viroid Evolution. Viruses. 2009; 1(2):241-254.
Elena, Santiago F.; Gómez, Gustavo; Daròs, José-Antonio. 2009. "Evolutionary Constraints to Viroid Evolution." Viruses 1, no. 2: 241-254.