LUCA Dates Back 4.2 Billion Years, Rewriting the Story of Life
New analysis places LUCA—the Last Universal Common Ancestor—on Earth about 4.2 billion years ago, roughly 400 million years after Earth's formation, based on genetic mutation rates and shared cellular machinery. The study suggests LUCA was a simple prokaryote with an immune system and likely lived in a recycling microbial ecosystem, meaning all modern life traces back to this ancient ancestor, while the exact path from LUCA to later life remains to be fully understood.
