All life on Earth originated from a single ancestor, older than previously thought.

Scientists caution that our understanding of LUCA is still evolving.

Scientists have rewritten the history of life on Earth with a new estimate of the age of LUCA, or the Last Universal Common Ancestor, which is generally recognized as the common ancestor of all living things, thanks to a groundbreaking study.

The study published in Natural ecology and evolutionThe data suggests that LUCA lived about 4.2 billion years ago, much closer to the origin of the Earth than previously thought.

LUCA, the common ancestor of all living things and not the first life form, has been a subject of debate among scientists for centuries. Fossil evidence of life dates back as far as 3.4 billion years, yet this study suggests that LUCA may be close to the same age as Earth. The genetic code and DNA replication, two vital biological processes, may have evolved almost immediately after the planet formed.

The research team analyzed 700 genomes of bacteria, archaea, and fungi and built the LUCA genome, excluding eukaryotes such as plants and animals that evolved later. They found 57 gene families that account for the evolutionary relationships of these organisms in their study.

Their results suggest that LUCA is a highly complex organism, a type of modern bacteria or archaea that does not have the ability to photosynthesize. The study proposes a new method for determining the age of LUCA using homologous genes and fossil data to solve the problem of the lack of direct fossil evidence for the early days of the Earth.

This LUCA reconstruction represents a major advance in our understanding of the evolution of life on Earth. However, the researchers’ work has ensured that their findings are not the final ones. As new organisms are discovered and technology improves, it is very likely that our interpretation of LUCA will evolve, even to the point of giving us more depth in our knowledge of the ancient beginnings of life.