Theoretical origin of life: a 'what if' study (Introduction)

by David Turell , Tuesday, October 01, 2024, 23:17 (53 days ago) @ David Turell

Using lab DNA in a theoretical setting:

https://phys.org/news/2024-10-scientists-plausible-geological-life-earth.html

"Researchers have discovered a plausible evolutionary setting in which nucleic acids—the fundamental genetic building blocks of life—could enable their own replication, possibly leading to life on Earth.

"The study, published today as a Reviewed Preprint in eLife, was described by editors as important work with convincing evidence to show how a simple geophysical setting of gas flow over a narrow channel of water can create a physical environment that leads to the replication of nucleic acids. The work will be of interest to scientists working on the origin of life, and more broadly, on nucleic acids and diagnostic applications.

***

"...strands of RNA need not only to replicate into a double-stranded form, but also to separate again to complete the replication cycle. Strand separation, however, is a difficult task at the high salt and nucleic acid concentrations required for replication.

"'Various mechanisms have been studied for their potential to separate DNA strands at the origin of life, but they all require temperature changes that would lead to degradation of nucleic acids," says lead author Philipp Schwintek.

***

"'We investigated a simple and ubiquitous geological scenario where water movement through a rock pore was dried by a gas percolating through the rock to reach the surface. Such a setting would be very common on volcanic islands on early Earth which offered the necessary dry conditions for RNA synthesis."

"The team built a laboratory model of the rock pore featuring an upward water flux evaporating at an intersection with a perpendicular gas flux, which leads to an accumulation of dissolved gas molecules at the surface. At the same time, the gas flux induces circular currents in the water, forcing molecules back into the bulk. To understand how this model would affect nucleic acids within the environment, they used beads to monitor the dynamics of the water flow and then tracked the movement of fluorescently labeled short DNA fragments. (my bold)

"'Our expectation was that continuous evaporation would lead to an accumulation of DNA strands at the interface," says Schwintek. "Indeed, we found that water continuously evaporated at the interface but the nucleic acids in the aqueous face accumulated near the gas/water interface." Within five minutes of starting the experiment, there was a three-fold accumulation of DNA strands, whereas after an hour, there were 30 times more DNA strands accumulated at the interface.

"Although this suggests that the gas/water interface allows for a sufficient concentration of nucleic acids for replication to occur, separation of the double DNA strands is also necessary. Usually a change in temperature is required, but when the temperature is constant, changes in salt concentration are necessary.

"'We hypothesized that the circular fluid flow at the interface provided by the gas flux, alongside passive diffusion, would drive strand separation by forcing the nucleic acids through areas with different salt concentrations," explains senior author Dieter Braun, Professor of Systems Biophysics at Ludwig-Maximilians-Universität München.

***

"Although nucleic acids and salts accumulated near the gas-water interface, in the bulk of the water the concentrations of salt and nucleic acids remained vanishingly low. This prompted the team to test whether nucleic acid replication could really happen in this environment, by adding nucleic acids labeled with a fluorescent dye and an enzyme that can synthesize double-stranded DNA into the laboratory model of the rock pore. Unlike normal laboratory DNA synthesis reactions, the temperature was maintained at a constant temperature and the reaction was instead exposed to the combined water and gas influx.

"After two hours, the fluorescent signal had increased, indicating an increased number of replicated double-stranded DNA molecules. Yet, when the gas and water influx were switched off, no increase in fluorescence signals was observed, and therefore no increase in double-stranded DNA was seen.

"'In this work we investigated a plausible and abundant geological environment that could trigger the replication of early life," concludes Braun. "We considered a setting of gas flowing over an open rock pore filled with water, without any change in temperature, and found that the combined gas and water flow can trigger salt fluctuations which support DNA replication. (my bold)

"'Since this is a very simple geometry, our findings greatly extend the repertoire of potential environments that could enable replication on early planets.'"

Comment: this is a totally laughable waste of grant money. IF DNA appeared in this setting DNA strands will congregate near the interface of gas and water. IT did, which means that IF naturally appearing DNA was in this setting with the correct enzyme then may be a miracle would occur and life would appear. But all we see is lab supplied DNA and enzyme. The wole field is a cesspool of lost grant money supplied by our tax money.