An international team of researchers led by the University of Bristol has shed more light on LUCA (Last Universal Common Ancestor).
Key points
- LUCA is the hypothesized common ancestor from which all modern cellular life, from single celled organisms like bacteria to the gigantic redwood trees (as well as us humans) descend.
- LUCA is the node on the tree of life from which the fundamental prokaryotic domains (Archaea and Bacteria) diverge.
- Modern life evolved from LUCA from various different sources: the same amino acids used to build proteins in all cellular organisms, the shared energy currency (ATP), the presence of cellular machinery like the ribosome and others associated with making proteins from the information stored in DNA, and even the fact that all cellular life uses DNA itself as a way of storing information.
- The research team used a genetic equivalent of the familiar equation used to calculate speed in physics to work out when LUCA existed, arriving at the answer of 4.2 billion years ago — just 400 million years after the formation of Earth and our Solar System.
- A researcher associated with the study said “our study showed that LUCA was a complex organism, not too different from modern prokaryotes, but what is really interesting is that it’s clear it possessed an early immune system, showing that even by 4.2 billion years ago, our ancestor was engaging in an arms race with viruses.”
