Origin and Evolution of RNA-Dependent RNA Polymerase

Area of Science:

• * Origin of Life Research
• * Molecular Evolution
• * Virology

Background:

• * RNA-dependent RNA polymerases (RdRp) are crucial enzymes for RNA viruses.
• * Their ancient origins and evolutionary pathways remain incompletely understood.
• * Understanding RdRp evolution offers insights into early life and viral emergence.

Purpose of the Study:

• * To reconstruct the evolutionary history of RdRp from the origin of life.
• * To investigate the ancestral RdRp structure and its relation to early genetic systems.
• * To elucidate the evolutionary trajectory of RNA viruses based on RdRp lineage.

Main Methods:

• * Phylogenetic analysis to trace RdRp origins from tRNA ancestors.
• * Reconstruction of ancestral RdRp protein domains and cofactor-binding sites.
• * Comparative analysis of RdRp evolution across different viral groups.

Main Results:

• * RdRp likely originated from proto-transfer RNAs (tRNAs) involved in early translation.
• * The ancestral RdRp featured a cofactor-binding site for simple molecules and ribonucleotides.
• * RdRp evolution shows distinct pathways for single-stranded and double-stranded RNA viruses, driven by genome organization pressures.

Conclusions:

• * RdRp emerged from early RNA-based genetic systems, predating DNA.
• * The study proposes a detailed evolutionary route for RdRp and RNA viruses.
• * Findings suggest an ancient origin for RNA viruses linked to early polymerases.