The history of life on Earth is indeed a fascinating epic spanning billions of years. A recent study published in the journal Nature suggests that the last universal common ancestor (LUCA) may have appeared around 4.2 billion years ago, much earlier than previously thought. This finding challenges the established timeline of life’s evolution and provides new insights into the early conditions on Earth that allowed life to flourish.
Recent research led by the University of Bristol suggests that LUCA (Last Universal Common Ancestor) lived around 4.2 billion years ago, just a few hundred million years after Earth formed. This finding challenges earlier estimates that placed LUCA’s existence between 3.5 and 3.8 billion years ago. The team refined this timeline using genetic and fossil data, along with advanced analytical methods.
The Last Universal Common Ancestor (LUCA) is often described as a primitive microbe, but its exact nature remains unclear. According to Dr. Jack Szostak, a Nobel Prize-winning physician, LUCA was likely a single-celled organism with a cell membrane that used DNA, RNA, and proteins for its biological functions. This description is crucial for understanding the early mechanisms of life and the foundations of modern biology.
In a new study, researchers identified about 2,600 protein-coding genes attributed to LUCA, significantly higher than previous estimates of around 100 genes. These genes provide valuable insights into LUCA’s biological capabilities, suggesting it already had complex metabolic and reproductive mechanisms, as well as an immune system.
Dr. Edmund Moody, the lead author of the study, explained that the evolutionary history of genes is complicated by their exchange between lineages, requiring complex evolutionary models to reconcile gene history with species genealogy.
Living conditions on Earth during the time of LUCA were extreme. The oceans were very hot, the volcanoes were highly active, and the atmosphere was saturated with toxic gases. Yet, it was precisely such an environment that served as the habitat for our common ancestor. These conditions likely played a crucial role in the evolution of the first forms of life. According to a study published by the University of Chicago, the first organisms had to adapt to a hydrothermal environment rich in minerals and chemical compounds.
A new study published in the journal Nature Ecology & Evolution used advanced phylogeny techniques to identify universal genetic markers present in archaea and bacteria. By analyzing 574 archaeal genomes and 3,020 bacterial genomes, the researchers identified 59 genetic markers suitable for phylogeny containing both archaea and bacteria.
To achieve this, they compiled an unreduced list of markers used in previous studies and mapped them to profiles in the COG (Orthologous Gene Groups), arCOG, and TIGRFAM databases. These databases are used for genome annotation and identification of protein families, mainly in bacteria and archaea. Appropriate proteins were then extracted and analyzed to verify their presence in the genomes of archaea and bacteria.
Dr. Tom Williams from the Bristol School of Biological Sciences highlights the study’s use of a gene-tree matching approach on a diverse dataset of archaea and bacteria, which helps us understand LUCA’s lifestyle with some certainty.
The researchers aligned genetic marker sequences and constructed phylogenetic trees using complex substitution models. They conducted rigorous tests to eliminate horizontal gene transfer and duplications that could distort the results. By applying molecular dating techniques, they estimated that LUCA existed around 4.2 billion years ago. This data enabled them to reconstruct a reliable phylogenetic tree and trace the evolution of genes from this common ancestor.
Technological advances and new genetic research techniques are allowing scientists to delve deeper into the history of the origin of life on Earth, including LUCA. Recent studies have used genetic databases of thousands of modern microorganisms to identify gene families that may have been present in LUCA. The results of these studies help us understand more about how life evolved from this common ancestor.
“I think if we find life elsewhere, it will be very similar to modern life, at least from a chemical point of view,” said William Martin, a professor of evolutionary biology at Heinrich Heine University of Düsseldorf, in a paper on LUCA published by NASA in 2017.
The latest data on LUCA is forcing us to reconsider our understanding of the history of life on Earth. They also highlight the incredible resilience and ingenuity of life capable of thriving in conditions that today we would call inhospitable. These discoveries remind us that, despite our diversity, all life forms on Earth share a deep and ancient connection that goes back to the earliest moments of our planet.
History, they say, is written by the victors. But what happens when the victors have…
On August 7, 1985, a group of Soviet astronomers made a discovery that would baffle…
In the opening months of 2025, the world stands at a pivotal crossroads, a moment…
Imagine a crisp, moonlit night, the kind where the air is thick with mystery and…
In a stunning turn of events that has captivated both professional astronomers and skywatching enthusiasts,…
A century-old secret may soon see the light of day. Deep within the labyrinthine Apostolic…