Ancestor cell of animals and plants lived on hydrogen, not oxygen: Chinese study

South China Morning Post

20-05-2025

A team of Chinese
scientists has traced the ancestor of animals and plants to a hydrogen-metabolising cell that existed before the Great Oxidation Event, a pivotal period that occurred at least 2.1 billion years ago and led to the formation of the Earth's oxygen-rich atmosphere.
The study suggests that the last common ancestor of eukaryotes lived around 2.72 billion years ago under oxygen-deficient conditions.
Eukaryotes are cells or organisms characterised by a membrane-bound nucleus. They are the foundation of complex, multicellular life including all animals, plants and fungi, as well as many unicellular organisms.
'The origin of eukaryotic cells has long remained a mystery,' the team of researchers from East China Normal University and Shenzhen University said in a paper published in the peer-reviewed journal Nature earlier this month.
The findings of the team support the hydrogen hypothesis for the origin of eukaryotes, challenging earlier findings about the lineage of this common ancestor.
As eukaryogenesis has allowed for the development of complex life on Earth, understanding its origins can uncover more insights into the evolution of life. It could also have implications for the exploration of life in outer space – by shedding light on the conditions and processes that might allow complex life to arise elsewhere in the universe.