©Sangharsh Lohakare via Unsplash
The ancient genes could reveal a truth we had only touched upon until now: life on Earth may have begun much earlier than we imagine.
Some genes present in almost all living organisms today existed - and were duplicated - even before the appearance of the universal common ancestor from whom we are all descended. A discovery that touches not only evolutionary biology, but also a much larger question: how did life arise? 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 that one the 'last universal common ancestor': the most distant point we can study today with the tools of evolution.
Yet one detail changes the perspective. When this ancestor lived, many fundamental features were already in place: cells had well-structured membranes and genetic information was stored in DNA. In other words, life was no longer 'under construction', but already surprisingly well organized. To really understand how everything began, we need to go back further in time.
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 tracks of some rare, ancient genes that have survived until today.
Goldman explains it clearly: even though the universal common ancestor is the oldest organism we can analyze with current methods, some of the genes in its genome were much older. And that's where the ancient genes come in.
Universal paralogs
The researchers are focusing on a special group of genes called 'universal paralogs'. In biology, a paralog is a gene that has been duplicated over time within the same genome. This happens all the time: small copying errors produce multiple versions of the same gene, which then specialize. A simple example: in humans, there are eight hemoglobin genes, all descended from a single original gene that appeared about 800 million years ago. Over time, each copy was given a slightly different function.
The universal paralogs, however, are slightly different. These are gene families that appear in at least two copies in the genomes of almost all living organisms. That means their duplication occurred before the emergence of the universal common ancestor. So before four billion years ago.
In other words, these genes bear witness to an era we previously thought unreachable. And it's precisely thanks to new technologies - such as advanced computational tools, artificial intelligence and hardware optimized for genetic analysis - that we can now reconstruct that invisible history. The researchers analyzed all universal paralogs known so far, finding a surprising element: they are all involved in the production of proteins or in the transport of molecules through cell membranes.
This is not a detail of minor importance. It means that among the very first biological functions to appear on Earth were protein synthesis and transport through primitive membranes. The very foundations of cellular life.
In a parallel study, 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 with computational biology. And the result was striking: even in its simplest form, this protein was able to bind to membranes and interact with the system that produces proteins. In other words, primordial cells, however rudimentary, were already functional. Not random clumps of molecules, but systems that could organize themselves.
According to Betül Kaçar, following the tracks of ancient genes means connecting the very first steps of life with the most modern scientific tools. It's a way to turn the deepest questions of evolution into testable hypotheses. And perhaps in the future, the identification of new universal paralogs will allow us to go back even further and reconstruct a chapter of Earth's history that until now has remained in obscurity.
Understanding how life originated is not just an academic matter. It's a way of realizing how fragile, rare and precious the biological complexity we take for granted is. And the ancient genes, silent but tenacious, are quietly beginning to tell us.
(©Cell Genomics via GreenMe.it 2026/Managing Editor: Julie Morgan - The Press Junction/Picture: ©picture alliance/dpa/dpa-POOL | Peter Kneffel)