Scientists point out that our understanding of LUCA is still evolving.

Thanks to a groundbreaking study, scientists have rewritten the history of life on Earth with a new estimate of the age of LUCA (the last universal common ancestor), which is widely accepted as the common ancestor of all living things.

The study, which was published in Natural ecology and evolutionsuggests that LUCA lived approximately 4.2 billion years ago, which is much closer to the formation of the Earth than previously thought.

LUCA, a common ancestor of all organisms and not the first form of life, has been a controversial topic among scientists for centuries. Fossil evidence of life dates back as far as 3.4 billion years, yet this study suggests that LUCA could be roughly as old as Earth. The genetic code and DNA replication, two of the biological processes essential to life, could have evolved almost immediately after the planet’s formation.

The research team analyzed 700 genomes of bacteria, archaea and fungi and constructed the genome of LUCA, excluding later-evolved eukaryotes such as plants and animals. In their study, they found 57 gene families responsible for the evolutionary relationships of these organisms.

Their results show LUCA to be a very complex organism, a type of modern bacterium or archaea, incapable of photosynthesis. The study proposed a new method for dating LUCA that uses paralog genes and fossil data to solve the problem of little direct fossil evidence for the early Earth.

This LUCA reconstruction represents a significant advance in our understanding of the evolution of living organisms on Earth. However, the research has ensured that its conclusions are not the final ones. As new organisms are discovered and technology advances, it is very likely that our interpretation of LUCA will continue to evolve, to the point where we can deepen our knowledge of the origins of life.