How a neutral evolutionary ratchet can build cellular complexity

摘要: Summary Complex cellular machines and processes are commonly believed to be products of selection, it is typically understood the job evolutionary biologists show how selective advantage can account for each step in their origin subsequent growth complexity. Here, we describe complex might instead evolve absence positive selection through a process ‘‘presuppression,’’ first termed constructive neutral evolution (CNE) more than decade ago. If an autonomously functioning component acquires mutations that make dependent function on another, preexisting or process, if there multiple ways which such dependence may arise, then inevitably will arise reversal independence unlikely. Thus, CNE unidirectional ratchet leading complexity, complexity equated with number components steps necessary carry out process. explain ‘‘functions’’ seem little sense terms economy, like RNA editing splicing, but also contribute clear benefit cell, ribosome, organismal overall. We suggest CNE-based scenarios these other cases less forced selectionist adaptationist narratives generally told. 2011 IUBMB Life, 63(7): 528–537,