Journal of Molecular Biology
Available online 19 February 2020
In Press, Journal Pre-proof
Perspective
A Theoretical Framework for Evolutionary Cell Biology
MichaelLynch, BogiTrickovic
Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287
Received 29 October 2019, Revised 20 January 2020, Accepted 4 February 2020, Available online 19 February 2020.
Center Director and Professor, Biodesign Center for Mechanisms of Evolution
Highlights
• Natural selection is not an all-powerful mechanism, and other evolutionary mechanisms (genetic drift and mutation) affect the stationary distribution of the trait value. Thus, evolution cannot be always treated as an optimization process.
• For a trait to evolve, the benefit that it confers to an individual must outweigh the cost of the trait. This holds for any trait, ranging from nutrient intake and motility, to signal sensing and cell wall. The costs are defined in terms of the amount of ATP that has to be consumed for the production and maintenance of the trait.
• While the previous studies focused on the cost of the gene, we extend this approach to the costs of common cellular features; Namely, bacterial motility and cell envelope.
Abstract
One of the last uncharted territories in evolutionary biology concerns the link with cell biology. Because all phenotypes ultimately derive from events at the cellular level, this connection is essential to building a mechanism-based theory of evolution. Given the impressive developments in cell biological methodologies at the structural and functional levels, the potential for rapid progress is great. The primary challenge for theory development is the establishment of a quantitative framework that transcends species boundaries. Two approaches to the problem are presented here: establishing the long-term steady-state distribution of mean phenotypes under specific regimes of mutation, selection, and drift; and evaluating the energetic costs of cellular structures and functions. Although not meant to be the final word, these theoretical platforms harbor potential for generating insight into a diversity of unsolved problems, ranging from genome structure to cellular architecture to aspects of motility in organisms across the Tree of Life.
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EXCERPT:
One of the most significant problems in the broader body of biological thinking is the common assumption that all observed aspects of biodiversity are products of natural selection. …
With this mind set, evolutionary biology becomes little more than a (sometimes endless) exercise in dreaming up the supposed agents of selection molding one’s favorite aspect of phenotypic diversity. …
However, we now know that this unwavering belief in the limitless power of natural selection is untenable. [Emphasis added.]
EXCERTO:
Um dos problemas mais significativos no corpo mais amplo do pensamento biológico é a suposição comum de que todos os aspectos observados da biodiversidade são produtos da seleção natural. ...
Com essa mentalidade, a biologia evolucionária se torna pouco mais que um exercício (às vezes interminável) de sonhar com os supostos agentes de seleção que moldam o aspecto favorito da diversidade fenotípica. ...
No entanto, sabemos agora que essa crença inabalável no poder ilimitado da seleção natural é insustentável. [Enfase adicionada.]
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