Study Dates LUCA to 4.2 Billion Years Ago, Finds Early Immune System
Updated
Updated · Yahoo! Voices · Aug 12
Study Dates LUCA to 4.2 Billion Years Ago, Finds Early Immune System
3 articles · Updated · Yahoo! Voices · Aug 12
Summary
4.2 billion years ago is the new estimate for LUCA, the last universal common ancestor, placing it about 400 million years after Earth formed.
Gene comparisons across living species and mutation counts drove the revision, with researchers using evolutionary models to work backward despite genes moving between lineages.
The same analysis suggests LUCA was a simple prokaryote that already had an immune system, implying viruses were infecting life at a very early stage.
Researchers also infer LUCA was part of a wider microbial ecosystem whose waste fed other microbes, extending the picture of organized life deep into the Hadean Eon.
The findings, published in Nature Ecology & Evolution, push the timeline beyond the long-cited roughly 4 billion years but still leave life’s pre-LUCA origins unresolved.