THE primordial genes they could tell us a truth that we had only touched upon until now: life on Earth could have begun much earlier than we imagine. Some genes present today in almost all living organisms existed – and had already duplicated – even before the universal common ancestor from which we all descended appeared.
A discovery that is not just about evolutionary biology, but touches on a bigger question: How did life come about? And above all, what was there before?
What were the first cellular functions that appeared billions of years ago?
Every current life form, from bacteria to plants to humans, shares an ancestor that lived about four billion years ago. Scientists call it the “last universal common ancestor”: it is the most remote point that we can study today with the tools of evolution.
Yet, there is a detail that changes perspective. When this ancestor lived, many fundamental characteristics were already present: the cells had well-structured membranes and the genetic information was stored in DNA. In short, life was no longer “under construction”, but already surprisingly organised. To really understand how it all started, you have to go back even further.
A study published in Cell Genomics and conducted by Aaron Goldman of Oberlin College, Greg Fournier of the Massachusetts Institute of Technology and Betül Kaçar of the University of Wisconsin-Madison has identified a concrete trail: following the traces of some very rare, very ancient genes that have survived to this day.
Goldman explains it clearly: even if the universal common ancestor is the oldest organism we can analyze with current methods, some of the genes contained in its genome were much older. And this is where primordial genes come into the picture.
Universal paralogs
Researchers focus on a special group of genes called “universal paralogs.” In biology, a paralog is a gene that has duplicated over time within the same genome. It happens all the time: small copying errors produce multiple versions of the same gene, which then become specialized. A simple example: in humans there are eight hemoglobin genes, all derived from a single ancestral gene that appeared about 800 million years ago. Over time, each copy took on a slightly different function.
The universal paralogsHowever, they are something else. They are genetic families present in at least two copies in the genomes of almost all living organisms. This means that their duplication occurred before the birth of the universal common ancestor. Before four billion years ago.
In other words, these geniuses are witnesses of an era we thought unattainable. And it is precisely thanks to new technologies, such as advanced computational tools, artificial intelligence, hardware optimized for genetic analysis, that today we can reconstruct that invisible history. Scholars have analyzed all the universal paralogs known so far and have found a surprising element: all are involved in the production of proteins or the transport of molecules across cell membranes.
It’s not a minor detail. It means that among the very first biological functions that appeared on Earth there would have been protein synthesis and transport across primitive membranes. The very foundations of cellular life.
In parallel work, the team even reconstructed the ancestral version of one of these proteins in the laboratory. Not a theoretical model, but a real protein, obtained by combining evolutionary biology and computational biology. And the result was surprising: even in its simplest form, this protein was able to bind to membranes and interact with the system that produces proteins. Ergo, the primordial cells, however rudimentary, were already functional. Not random clusters of molecules, but systems capable of organizing themselves.
According to Betül Kaçar, following the traces of primordial genes means connecting the very first steps of life to the most modern scientific instruments. It’s a way to turn evolution’s deepest questions into testable hypotheses. And perhaps, in the future, the identification of new universal paralogs will allow us to go even further, reconstructing a chapter of Earth’s history that has so far remained in the dark.
Because understanding how life was born is not just an academic question. It is a way to understand how fragile, rare and precious the biological complexity that we take for granted today is. And i primordial genessilent and obstinate, are starting to tell us.
