Less can be more: RNA-adapters may enhance coding capacity of replicators

Area of Science:

• Origin of Life Studies
• Molecular Evolution
• Systems Biology

Background:

• The RNA world hypothesis posits that RNA replicators preceded DNA and proteins.
• Complexity in modern organisms arose from these early RNA replicators.
• RNA molecules extensively modify other RNAs in contemporary life, suggesting a role in early evolution.

Purpose of the Study:

• To investigate the role of RNA-RNA modification in the evolution of prebiotic complexity.
• To model protocell evolution incorporating RNA-based self-modification tools.
• To understand how RNA-adapters influence genotype-phenotype mapping and coding capacity.

Main Methods:

• Modeling protocell evolution with RNA replicators.
• Incorporating RNA-adapters for sequence modification via antisense base-pairing.
• Studying evolution towards specific functional RNA structures while avoiding toxic misfolded structures.
• Analyzing the impact of mutation rates and redundant coding on evolvability.

Main Results:

• Protocells with RNA-modification capabilities achieve high fitness even under high mutation rates.
• Toxicity of misfolded RNA structures impedes self-modification machinery evolution.
• High mutation rates can paradoxically promote complex coding structure evolution by reducing redundant coding.
• RNA-adapters enhance genotype-phenotype mapping, increasing genome coding capacity.

Conclusions:

• RNA-RNA modification is a viable mechanism for increasing complexity in early replicators.
• The evolution of self-modification is sensitive to mutation rates and the cost of non-functional structures.
• Protocell models demonstrate how RNA-adapters can overcome information thresholds and enhance genome efficiency.