Because some of these divergences have fossil records, the team was able to calibrate their molecular clock and confidently push LUCA’s existence back from the previous estimate of 3.8 billion years to 4.2 billion years.
LUCA: Surprisingly Sophisticated
Despite existing in a world without oxygen, LUCA wasn’t a primitive chemical blob. The analysis suggests LUCA had:
- DNA-based genetics
- Ribosomes for protein synthesis
- ATP metabolism (the universal energy currency in cells)
It may have even had a basic immune system, defending itself against ancient viral threats.
“This allows us to say with some confidence—and assess that level of confidence—on how LUCA lived,” said Dr. Tom Williams, a co-author of the study.
Professor Davide Pisani added that LUCA was already “exploiting and changing its environment,” laying the biological foundation for life as we know it.
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Where LUCA Lived and What It Ate
LUCA likely thrived in hydrothermal vent environments—hot, mineral-rich underwater fissures that many scientists believe could be the cradle of life. These locations offer chemical gradients and energy sources that would’ve powered LUCA’s early metabolism.
