Interdependence, Reflexivity, Fidelity, Impedance Matching, and the Evolution of Genetic Coding

Area of Science:

• Molecular Biology
• Origins of Life
• Biochemistry

Background:

• The prevailing view posits ribozymes preceded polypeptide aminoacyl-tRNA synthetases (aaRS) in genetic coding.
• This RNA world hypothesis faces challenges in explaining the transition to modern molecular biology.

Purpose of the Study:

• To propose a unifying rationale for the simultaneous emergence of genetic coding processes.
• To challenge the necessity of a prior RNA world for the origin of the Central Dogma.

Main Methods:

• Analysis of aminoacyl-tRNA synthetase (aaRS) structural biology and gene origins.
• Mapping amino acid physical chemistry to tRNA identity elements.
• Theoretical modeling of genetic coding emergence dynamics.

Main Results:

• Two aaRS classes likely originated from opposite gene strands, implying a simple genetic alphabet and stabilizing coding specificity.
• Amino acid properties directly map to tRNA identity elements, enabling reflexive sensing in aaRS.
• Bootstrapping of coding is intrinsic to polypeptide aaRS, not possible in an RNA world.

Conclusions:

• The Central Dogma likely emerged from a peptide•RNA partnership, not a gradual replacement of ribozymes.
• Interdependent aaRS, reflexive bootstrapping, and comparable error rates support de novo emergence of genetic coding.
• This model explains the continuous preservation of functional meaning in genetic code evolution.