How did the first forms of life emerge on Earth around 4 billion years ago? The relentless search by scientists to understand the origins of life has recently made a significant breakthrough.
A team from the Scripps Research Institute has discovered a plausible path explaining the formation and chemical evolution of protocells, these precursors to living cells. These findings, published in the journal
Chem, could shed light on the early evolutionary process and the complexification of life on our planet.
Protocells, a spherical assembly of lipids, are considered the ancestors of cells. But how could these simple structures diversify to give rise to life as we know it? The answer might lie in a chemical process called phosphorylation, according to Scripps scientists. This process, involving the addition of phosphate groups to molecules, could have promoted the emergence of more complex double-chain protocells, capable of housing a variety of chemical reactions and dividing.
To reach these conclusions, the team led by Ramanarayanan Krishnamurthy and Ashok Deniz recreated prebiotic conditions in the laboratory, using fatty acids and glycerol, substances likely present on early Earth. By adding various chemical components and modifying the reaction environment (temperature, pH, metal ions), they observed the formation of vesicles, structures similar to protocells. These experiments showed that fatty acids and glycerol could undergo phosphorylation, leading to more stable and diversified vesicles, essential for the evolution of life.
This work not only reveals a possible pathway for the appearance of phospholipids, fundamental building blocks of life, but also opens the door to a better understanding of the dynamic mechanisms behind the fusion and division of protocells. The next step for researchers will be to explore these dynamic processes to deepen our understanding of the evolution of early forms of life on Earth.