Limited Sequence Diversity Within a Population Supports Prebiotic RNA Reproduction.

Area of Science:

• Origin of Life Studies
• Prebiotic Chemistry
• Molecular Evolution

Background:

• The emergence of life necessitates self-replicating informational polymers.
• Prebiotic environments likely contained limited, short RNA sequences.
• The required sequence diversity for RNA reproduction remains an open question.

Purpose of the Study:

• To investigate the impact of sequence diversity on RNA reproduction onset.
• To determine the optimal diversity level for prebiotic RNA replication.
• To explore the role of population size in RNA reproduction.

Main Methods:

• Computer simulations of template-directed recombination and ligation.
• Modeling RNA populations with varying sequence diversity.
• Analysis of RNA reproduction probability as a function of diversity and population size.

Main Results:

• RNA reproduction is improbable in both low and high diversity populations.
• An intermediate level of sequence diversity robustly enables RNA reproduction.
• Increased population size broadens the range of intermediate diversity for reproduction.
• Emergent reproducible RNAs form autocatalytic networks, collectively enhancing information capacity.

Conclusions:

• Abiotic RNA molecules, even with limited abundance and diversity, can initiate self-catalytic reproduction.
• Spontaneous network formation is a plausible mechanism for early RNA replication and information expansion.
• Intermediate sequence diversity is a critical factor for the transition from simple prebiotic chemistry to life-like reproduction.