🧬 The origin of life hidden in the smallest bricks

Tiny fragments could tell the story of life's beginnings.

Genes are like a recipe that tells cells how to function. But the origin of this "recipe" remains poorly understood. To move forward, researchers suggest looking not only at DNA, but also at proteins, which concretely carry out actions in cells.

The study published in Journal of Molecular Biology focuses on dipeptides. These are very small pieces of proteins, formed by two amino acids linked together. They can be seen as elementary bricks, from which more complex structures are built.


To understand their role, scientists analyzed billions of dipeptides in very diverse organisms. They compared this data with other essential elements, such as transfer RNAs. These molecules serve as intermediates to assemble proteins from gene instructions.

They observed that everything evolves in a consistent manner. Dipeptides, transfer RNAs, and protein structures follow the same order of appearance. This indicates that the genetic code was built progressively, by adding new "bricks" over time.

Specifically, some simple amino acids would have appeared first. Then, other more complex ones were added, allowing proteins to become more efficient. This process would also have improved precision, avoiding errors during protein fabrication.

Researchers believe that proteins played a central role from the beginning. They would be more efficient than RNA for carrying out chemical reactions. RNA would then have taken on an important role for storing and transmitting information. Even today, life relies on this collaboration. DNA and RNA store information, while proteins execute tasks. A machine called the ribosome reads the instructions and assembles amino acids in the correct order.

One result strengthens this idea. Dipeptides often appear in reversed pairs, like "AB" and "BA". This indicates an underlying rule. It is not just a random accumulation of combinations: there is a form of symmetry, thus an organization.

Ultimately, this work shows that the genetic code would not have appeared all at once. It would have been built step by step, from simple elements, following a structured logic that allowed the emergence of life as we know it.