Before DNA, Did Structured Environments Give Chemistry Its First Meaning-Like Patterns?

Modern biology runs on information. DNA stores it, RNA helps interpret it, and proteins carry out its instructions. But this familiar story leaves a deeper question:

Where did biological information come from before genes existed?

Before DNA, accurate replication, or anything like a genetic code, chemistry had to cross a threshold. Molecular matter had to begin behaving less like random chemistry and more like an organized, information-bearing system.

A recent Metacodon study published in BioSystems explores one possible route across that threshold. The article, “Evolution of Pre-Genetic Semantic Information in Protocells Under Variable Inheritance Fidelity,” used a computational protocell model called Model B to test whether meaning-like molecular relationships could emerge before genes.

The central finding: under specific conditions, structured environments, weak molecular biases, and partial inheritance can allow protocell-like systems to develop predictive relationships between molecular patterns and chemical outcomes.

This is not a genetic code. There are no codons, ribosomes, proteins, or DNA in the model. But the result suggests that a primitive form of informational organization may be possible before modern genetics.


The environment as life’s first scaffold

Early Earth was not a uniform chemical soup. It was patterned.

Mineral surfaces, drying pools, thermal gradients, chemical patches, compartments, and local differences in molecular abundance could all have biased molecular interactions. Some places may have concentrated particular compounds. Some compartments may have retained molecular mixtures better than others.

That structure matters.

In a chemically uneven world, molecular interactions are not purely random. A local sequence pattern may be more likely to encounter one kind of molecule than another. A compartment may preserve some combinations long enough for patterns to persist. Repeated environmental bias can make certain molecular relationships more predictable over time.

In this view, the environment does not act like a genome. It does not store instructions or encode a program.

But it can provide a scaffold for information to arise.

Biological information may therefore have begun not as a code, but as a relationship: a reliable link between molecular structure and chemical consequence.


What Model B showed

Model B tested whether local molecular motifs could become predictive of associated metabolite classes without genetic replication.

They could.

When inheritance fidelity was high enough, motif–metabolite relationships became increasingly stable. In information-theoretic terms, mutual information increased between molecular patterns and chemical outcomes.

Metacodon describes this as pre-genetic semantic information, or more cautiously, proto-semantic information.

The term does not imply symbolic meaning, intention, or a full genetic code. It refers to something more primitive: a predictive, persistent, partly heritable relationship between a molecular pattern and a chemical consequence.

That distinction is important. Proto-semantic information is not yet genetic meaning. But it may represent one possible bridge between chemistry and later biological coding.


Why it matters

The study suggests that information-like structure can emerge before modern genetic replication.

This shifts the origin-of-life question. Instead of asking only how the first accurate replicator appeared, we can also ask how prebiotic systems first acquired reliable relationships between molecular structure and chemical consequence.

Model B points to three ingredients that may begin that process:

Together, these ingredients can generate predictive structure before DNA, before translation, and before a full genetic code.

The study also found that structured correlations can appear before strong fitness gains. That suggests early life may not have needed fully functional genetic information from the start. It may first have needed stable relationships that later evolution could refine.


Closing takeaway

Life may not have begun only when molecules learned to copy themselves.

It may also have begun when structured environments allowed matter to form reliable relationships between molecular patterns and chemical outcomes.

Before DNA stored biological information, the environment may have helped organize the first meaning-like patterns in chemistry.


Reference

Carr, M. J. (2026). “Evolution of Pre-Genetic Semantic Information in Protocells Under Variable Inheritance Fidelity.” BioSystems, 262, 105718. DOI: 10.1016/j.biosystems.2026.105718.