A survey of 2,000 genomes uncovered the LUCA or the Last Universal Common Ancestor of all life on Earth, which is also known as the microbial Eve.  The study published on July 25 in the journal Nature Microbiology reveals that LUCA was a microbe that loved heat, fed on hydrogen gas and lived in an environment without oxygen.

This supports the theory that all living things on Earth came from hydrothermal vents like the ones located near underwater volcanoes. The study involved analyzing 6.1 million genes from prokaryotes, which are single-celled microscopic organisms that do not have nuclei including bacteria.

The team led by William Martin, an evolutionary biologist at Heinrich Heine University in Dusseldorf, Germany, found that only 355 of these gene families were found in modern organisms, which made these most likely to be traced back from LUCA.

“We can get a glimpse of how and where our most ancient ancestors lived, and these environments are still around today, inhabited by cells whose lifestyle resembles that of LUCA,” says study senior author Martin.

The team concluded that microbial Eve was a thermophile. Like what many scientists believe, it fed on hydrogen gas.

The modern prokaryotes also live in similar environments, which include hot springs on land and the fissures found close to underwater volcanoes. The team cites Clostridia bacteria and methanogen archaea as two examples of prokaryotes.

Martin told Live Science that they would like to simulate the hydrothermal vent conditions billions of years ago to see if they can find out more about the basic building blocks of life.

However, some scientists claim this theory is inaccurate. John Sutherland of the University of Cambridge in England said that life did not develop underwater but in pools of water on land. Apparently, the sun’s ultraviolet light, which is a key ingredient to life, does not reach the hydrothermal vents.