Optimality Properties of a Proposed Precursor to the Genetic Code

TL;DR

This study evaluates a proposed doublet precursor to the genetic code, finding it less optimal than the canonical code, suggesting it was unlikely an intermediate in genetic code evolution and supporting the idea that code optimality reflects evolutionary processes.

Contribution

It provides an analysis of the optimality of a proposed genetic code precursor, challenging its role as an evolutionary intermediate and highlighting the evolutionary nature of code optimality.

Findings

The doublet precursor is less optimal than the canonical genetic code.

The results suggest the precursor was unlikely an intermediate in evolution.

Code optimality likely reflects evolutionary dynamics.

Abstract

We calculate the optimality of a doublet precursor to the canonical genetic code with respect to mitigating the effects of point mutations and compare our results to corresponding ones for the canonical genetic code. We find that the proposed precursor has much less optimality than that of the canonical code. Our results render unlikely the notion that the doublet precursor was an intermediate state in the evolution of the canonical genetic code. These findings support the notion that code optimality reflects evolutionary dynamics, and that if such a doublet code originally had a biochemical significance, it arose before the emergence of translation.