Scientists have uncovered a physical mechanism that may explain how the building blocks necessary for the origin of life on Earth formed. Researchers have long known that the building blocks of life – amino acids, nucleobases and sugars – were present in the early ocean, but they were very low in concentration.
In order for life to emerge, these building blocks needed to be combined and enriched into long-chain macromolecules. Identifying the process and mechanism driving this synthesis has been one of the largest questions concerning the origin of life.
Now, researchers at Texas A&M University in the US have found a mechanism that may have played a major role in combining these dilute chemical building blocks into the long-chain macromolecules necessary for life.
“In the early ocean, those building blocks were present in the environment,” said Victor Ugaz, professor at Texas A&M University. “They were there, but they were so dilute; there is a question about how they combined.
“So one area of interest is what kind of concentration mechanism could have existed to enrich those components to a point where they could start to form longer chains, more complex molecules,” Ugaz said.
The research team created a model system of cylindrical cells that mimic the structure of pores in mineral formations found near a recently discovered, new type of subsea hydrothermal vent. The temperature gradients present within these vents function just like an ordinary lava lamp, circulating fluid within the tiny pore spaces.
The team found that these flows are surprisingly complex and chaotic – meaning that individual paths follow a rough general pattern, but no trajectories are identical. This discovery made it possible to identify conditions where these flows are able to provide bulk homogenisation of the various organic molecules present in the vents, while at the same time transport them to catalytically active pore surfaces where they absorb and react, researchers said.
These flows naturally occur within hydrothermal pore networks providing an intriguing mechanism to explain how dilute organic precursors in the early ocean could have assembled into complex biomacromolecules.
This has been one of the key unanswered questions in the origin of life on Earth, and in extraterrestrial systems where similar hydrothermal environments have been discovered. The research was published in the journal Proceedings of the National Academy of Sciences.