A new study estimates that LUCA (Last Universal Common Ancestor), the last common ancestor of all life on Earth, existed around 4.2 billion years ago. This is significantly earlier than previous estimates.
LUCA is generally acknowledged as the common ancestor from which all living organisms on Earth evolved. However, its exact age has been controversial.
The study analyzed genomes of bacteria, archaea and fungi to reconstruct LUCA’s genome. They identified 57 gene families that show evolutionary relationships between these organisms.
The results suggest LUCA was a complex organism, similar to modern bacteria or archaea. It did not have the ability to photosynthesize.
The study provides a new way to date LUCA using paralogous genes and fossil evidence, since direct fossils of early life are scarce.
Dating LUCA to 4.2 billion years ago suggests key biological processes like DNA replication may have emerged very early after Earth’s formation.
However, scientists say understanding of LUCA is still evolving as more organisms are discovered and technology advances. The interpretation of LUCA will likely become more refined over time.
Source: NDTV
