Nobuto Takeuchi (University of Tokyo, Japan)

The origin of the central dogma through conflicting multilevel evolution

Seminar Theoretical Biology and Bioinformatics Group, Utrecht University
13 July 2018, 14.00, room Z409, Kruyt Building, de Uithof, Utrecht

Abstract

Molecular biology embodies three asymmetries between genomes and enzymes. Information flows from genomes to enzymes, but not from enzymes to genomes: informatic asymmetry (the central dogma of molecular biology). Genomes serve as templates, whereas enzymes serve as catalysts: functional asymmetry. Genomes are less abundant than enzymes per cell: numerical asymmetry. How did these asymmetries originate? Although existing theories can explain subsets of them, no theory has been able to explain all at one stroke. Here we provide such a theory by showing that all these asymmetries can spontaneously arise from conflicting multilevel evolution. Our model assumes a population of protocells, each containing a population of self-replicating catalytic molecules. The molecules are assumed to face a trade-off between providing catalysis and serving as templates, a dilemma that causes conflict between evolution at the molecular level and evolution at the cellular level. We find that this conflicting multilevel evolution forms a positive feedback with the asymmetric flow of information between the molecules, a destabilizing mechanism that induces symmetry breaking whereby the molecules differentiate into genomes and enzymes. Our work proposes an explicit mechanism for the origin of the fundamental molecular asymmetries underlying life, making the central dogma no longer a dogma.