Spatial models of persistence in RNA worlds: Exploring the origins of life

Authored by Thomas Caraco, WA Maniatty, N Lehman, BK Szymanski

Date Published: 2002

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

Prevailing hypotheses concerning origins of life assume that rare configurations of prebiotic polymers allowed their accurate replication, the precursor of biological reproduction. In particular, the ``RNA world{''} hypothesis equates the linear sequence of an RNA's nucleotides with its genotype. Individual RNA molecules may fold into different 3-dimensional structures, or conformers. Each such folding of a given genotype specifies a different phenotype. These phenotypes exhibit chemical properties that may result in replication of the genotype. Each phenotype has a fitness depending on replication rate, and so the phenotype distribution would be subject to natural selection. To model replication and extinction of prebiotic polymers, we combine computational and biological approaches. We consider a single genotype that can fold into two different phenotypes. Each phenotype's capacity to replicate its genotype depends on abiotic and biotic factors in the physical environment, which may change as time advances. We begin with a spatially detailed, individual based model, required for accurate modeling of small populations where the variability caused by random events among individual replicators dominates population dynamics. For efficient modeling of large populations where mean behavior tends to dominate, we derive a corresponding mean-field model that aggregates large, well mixed populations of common phenotypes to compare its behavior to the individual based version.

Tags

Evolution In-vitro