A 21st century adaptation of the Miller-Urey origin of life experiments

A 21st century adaptation of the Miller-Urey origin of life experiments
Miller-Urey experiments study the abiotic synthesis of organic compounds by creating an environment similar to that of the early earth. An electric discharge is applied to a mixture of gases representing the early earth's atmosphere and lightening. This is done in the presence of a liquid water reservoir, representing the early oceans, as well as with an apparatus simulating evaporation and precipitation. Credit: The Journal of Visualized Experiments

Today, January 21, JoVE, the Journal of Visualized Experiments, published a modern approach to a famed experiment that explored one of the most intriguing research questions facing scientists today—the origin of life on earth.

The protocol, titled Conducting Miller-Urey Experiments, is comprised of a modern and simplified approach to the method used by Dr. Stanley Miller and Dr. Harold Urey in 1953. Their research evaluated the possibility of organic compounds important for the origin of life to have been formed abiologically on early Earth.

"The results of this study showed that amino acids, the building blocks of life, could be formed under primitive Earth conditions," said Eric Parker of the original Miller-Urey Experiments. Parker is one of the researchers behind the simplified procedure, which he and his team developed at the Georgia Institute of Technology. Scientists from NASA—one of whom, Jeffrey Bada, was once a student of Dr. Miller's—and the Tokyo Institute of Technology were also involved.

"Miller was hesitant to encourage people to repeat the experiment due to the risk of inducing an explosion," said Parker, explaining why his lab chose to publish their version of the experiment in JoVE's signature step-by-step video format. "Often times, after reading a methods description it may not be fully clear how a certain research task was carried out," he said, "...Therefore, this article was written to inform interested researchers how to conduct the experiment safely, in part, by giving precise instructions on evacuating [ignitable gasses like oxygen, methane and hydrogen from] the reaction apparatus before initiating the spark."

The Miller-Urey experiment was a pioneering study regarding the abiotic synthesis of organic compounds with possible relevance to the origins of life. Simple gases were introduced into a glass apparatus and subjected to an electric discharge, simulating the effects of lightning in the primordial Earth's atmosphere-ocean system. The experiment was conducted for one week, after which, the samples collected from it were analyzed for the chemical building blocks of life. Credit: The Journal of Visualized Experiments

Despite these dangers, Parker said, there remains much interest among scientists to recreate the Miller-Urey experiment and to perform variations of it for testing new research ideas. He and his colleagues are preparing to publish a second article comparing their novel spark-discharge experimental results to original samples from the 1958 Miller-Urey cyanamide spark-discharge study that followed the landmark paper.

A 21st century adaptation of the Miller-Urey origin of life experiments
After a week of sparking in a Miller-Urey experiment, the contents within the reactant flask become visibly transformed. Miller-Urey's groundbreaking work is considered to be the first deliberate, efficient synthesis of biomolecules under simulated primitive Earth conditions. Credit: The Journal of Visualized Experiments

In the meantime, Parker and his colleagues hope that their JoVE video will encourage more research with Miller-Urey type experiments. Such efforts could help answer key questions in the origin of life field, such as which prebiotic conditions may have facilitated the synthesis of specific believed to be important for , Parker said.

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Jan 21, 2014
Cosmologists have know about the existence of organic molecules for a long time. They are not rare at all in the universe. It is everything after that:

Chirality of DNA, proteins and folding thereof.

and the biggest hurdle ... breaking the Law of Biogenesis.

Jan 22, 2014
Miller-Urey experiments are now mainly of interest for the pure RNA world theory, an RNA first theory. The theory that has phylogenetic support all the way to geochemistry is the dirty RNA world theory of alkaline hydrothermal vents - our most distant cousins. E.g. homologies of: cells, membranes, CHNOPS relative ratios, pH balance, chemiosmosis balance, chemiosmosis import, metabolic chemistry and (the key factor) electron bifurcating metal centers.

And aside from reactor configurations, there is little to learn here. As far as I know, the imported phosphates and NO (in the most likely basal metabolism) are mainly products of volcanism, not lightning.

@matt: There is no "the Law of Biogenesis" in biology what I know of. Besides, Lane, Martin, Russell et al has established the phylogeny that reaches all the way back into geochemistry. As of 2013 there were no longer any biological hurdle there.

Rather, a new question: how did RNA get involved in the established tree?

Jan 22, 2014
To address "biogenesis": It's really difficult to actually distinguish "what is life?" Are viruses life? Are chains of self-catalyzing chemicals life? There are a lot of precursor chemical patterns that can happen as non life, and then we draw an arbitrary distinction at some point to start calling it "life." This sequence, in its broadest strokes, is pretty well known. The fine details, as TLOM goes into above, (RNA world vs. proteins etc.) are yet to be found, but we expect we shall. And research like this can help us get there.

As for chirality of molecules, there's some speculation that the way organic molecules "bind" to clays and such that would have formed the early pools of life favored one handedness over another. It would be interesting to see if, for instance, Martian compounds from living things (should they exist) exhibit the same handedness, and if that is related to similar rock structures there.

Jan 22, 2014
RE: "Laws of biology, biogenesis, chemistry"...

It will be interesting to know how the universe works in the overall encompassing concept of life. My guess is that chemistry is "biased" so that life is an emergent property of it given the "correct set of conditions". I base this on the fact that all the evidence suggests that as soon as life could possibly manifest on Earth it did.

Complex life is another matter entirely. Intelligent life is a matter still further removed, and intelligent technological life is yet again likely another level on its own. All guesses to be sure, time will tell...

Jan 22, 2014
@shavera: I used to think that defining life is useless, like defining where a branch starts on a tree as you describe. (E.g. flush to the tree, at a horizontal cut for stem and branch, or some intermediate angle?)

But the alkaline hydrothermal (vent) theory has these homologies as I note. Cellular, electron bifurcating, alkaline geochemical systems are then sufficiently alive (with biochemical systems a subset) for evolution (either lamarckian or darwinian) to take place. There is still a fuzzy limit problem, but the problem is now not on the biological (darwinian evolution) side.

Jan 22, 2014
FWIW, and since I have to know this by tomorrow, the likelihood that the 8 homology traits I've tentatively ascribed to Russell's AHT would be independent are at least (from just picking them, not all possible) (1/8)^8 ~ 1/20*10^6 ~ 6*10^-8. I.e. the apriori likelihood that this theory is erroneous is far, far less than 3 sigma.

That doesn't mean it is the only remaining abiogenesis theory. But I don't think the other theories are testable as of yet.

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