How a Neutral Evolutionary Ratchet Can Build Cellular Complexity

0364838 - BC 2012 RIV US eng J - Journal Article
Lukeš, Julius - Archibald, J.M. - Keeling, P.J. - Doolittle, W.F. - Gray, M.W.
How a Neutral Evolutionary Ratchet Can Build Cellular Complexity.
Iubmb Life. Roč. 63, č. 7 (2011), 528-537. ISSN 1521-6543. E-ISSN 1521-6551
R&D Projects: GA MŠMT LC07032; GA MŠMT 2B06129
Institutional research plan: CEZ:AV0Z60220518
Keywords : neutral evolution * adaptation * selection
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 3.514, year: 2011

Here, we describe how complex machines might evolve in the absence of positive selection through a process of "presuppression," first termed constructive neutral evolution (CNE) more than a decade ago. If an autonomously functioning cellular component acquires mutations that make it dependent for function on another, preexisting component or process, and if there are multiple ways in which such dependence may arise, then dependence inevitably will arise and reversal to independence is unlikely. Thus, CNE is a unidirectional evolutionary ratchet leading to complexity, if complexity is equated with the number of components or steps necessary to carry out a cellular process. CNE can explain "functions" that seem to make little sense in terms of cellular economy, like RNA editing or splicing, but it may also contribute to the complexity of machines with clear benefit to the cell, like the ribosome, and to organismal complexity overall.
Permanent Link: http://hdl.handle.net/11104/0200215