# A Recipe to Evolve Complex Life Chemically on Earth

## TL;DR

This paper explores how tRNA molecules evolved chemically to enable life on Earth and suggests a pathway to recreate this process in the lab.

## Contribution

The paper proposes a detailed chemical evolution pathway for tRNA and its role in the origin of life.

## Key findings

- tRNA sequences are patterned in RNA repeats and inverted repeats.
- tRNA precursors were strongly chemically selected in pre-life.
- A simple pathway for tRNA-based life evolution can be assembled in labs.

## Abstract

Sequences of tRNAs are highly patterned in easily identifiable RNA repeats and RNA inverted repeats (stem–loop–stems). Because of patterning, the multi-step evolution of tRNA can be described in remarkable detail. To evolve life on Earth or another planet or the moon requires the evolution of tRNA or a tRNA-like molecule to act as a genetic adapter. To replace tRNA with an alternate or improved genetic adapter is a remarkably challenging problem, indicating strong chemical selection of tRNA precursors in pre-life. The genetic code, translation systems, and first proteins coevolved with tRNAomes (all of the tRNAs of an organism). Because the tRNA sequence can be separated into component parts, a simple pathway for chemical evolution of life and genetic coding can be described in sufficient detail to allow the assembly of a living entity in laboratories.