Groundbreaking study reveals life on Earth began 4.2B years ago
A new study by a global team of researchers suggests that life on Earth may have originated around 4.2 billion years ago, shortly after the planet's formation. Published in Nature Ecology & Evolution, the research focuses on the Last Universal Common Ancestor (LUCA), from which all modern cellular life is believed to descend. "We did not expect LUCA to be so old," said Dr. Sandra Alvarez-Carretero from the University of Bristol's School of Earth Sciences.
Tracing genetic footprints across diverse species
The research team traced LUCA's genetic history by comparing genes across various living species, and aligning these timelines with fossil records. This led them to conclude that LUCA existed around 4.2 billion years ago. "Our results fit with modern views on the habitability of early Earth," Alvarez-Carretero stated. The study also discovered that genetic fingerprints of LUCA are still present in a wide range of species, including those seemingly unrelated.
LUCA's complex biology and early immune system unveiled
The researchers also examined the physiological properties of modern species to model LUCA's biology. Lead author Dr. Edmund Moody said that the evolutionary history of genes is complicated by their exchange between lineages, requiring complex models to reconcile gene history with species genealogy. The study revealed that LUCA was a complex organism akin to modern prokaryotes, and had an early immune system, indicating an ancient battle with viruses.
LUCA's role in early Earth's recycling ecosystem
The research also suggests that LUCA was not just a passive organism but was actively exploiting and changing its environment. Co-author Tim Lenton, from the University of Exeter, noted that this indicates the existence of an early recycling ecosystem, where LUCA's waste would have served as food for other microbes. This finding provides further insight into the complex interactions and dependencies within ancient ecosystems on Earth.
