David Deamer, a biochemist at the University of California, Santa Cruz, has developed a device to mimic the conditions on early Earth.

Peter DaSilva for Quanta Magazine

David Deamer, a biochemist at the University of California, Santa Cruz, has developed a device to mimic the conditions on early Earth.

For the past 40 years, David Deamer has been obsessed with membranes. Specifically, he is fascinated by cell membranes, the fatty envelopes that encase our cells. They may seem unremarkable, but Deamer, a biochemist at the University of California, Santa Cruz, is convinced that membranes like these sparked the emergence of life. As he envisions it, they corralled the chemicals of the early Earth, serving as an incubator for the reactions that created the first biological molecules.

One of the great initial challenges in the emergence of life was for simple, common molecules to develop greater complexity. This process resulted, most notably, in the appearance of RNA, long theorized to have been the first biological molecule. RNA is a polymer — a chemical chain made up of repeating subunits — that has proved extremely difficult to make under conditions similar to those on the early Earth.

Deamer’s team has shown not only that a membrane would serve as a cocoon for this chemical metamorphosis, but that it might also actively push the process along. Membranes are made up of lipids, fatty molecules that don’t dissolve in water and can spontaneously form tiny packages. In the 1980s, Deamer showed that the ingredients for making these packages would have been readily available on the early Earth; he isolated membrane-forming compounds from the Murchison meteorite, which exploded over Australia in 1969. Later, he found that lipids can help form RNA polymers and then enclose them in a protective coating, creating a primitive cell.

Over the past few years, Deamer has expanded his membrane-first approach into a comprehensive vision for how life emerged. According to his model, proto-cells on the early Earth were made up of different components. Some of these components could help the proto-cell, perhaps by stabilizing its protective membranes or giving it access to an energy supply. At some point, one or more RNAs developed the ability to replicate, and life as we know it began to stir.

Deamer thinks that volcanic landmasses similar to those in Iceland today would have made a hospitable birthplace for his proto-cells. Freshwater pools scattered across steamy hydrothermal fields would be subject to regular rounds of heating and cooling. That cycle could have concentrated the necessary ingredients — including both lipids and the building blocks for RNA — and provided the energy needed to stitch those building blocks into biological polymers. Deamer is now trying to re-create these conditions in the lab. His goal is to synthesize RNA and DNA polymers.

Peter DaSilva for Quanta Magazine

Video: David Deamer explains how his laboratory mimics the extreme conditions found on volcanoes in the early Earth.

Quanta Magazine spoke with Deamer at a conference on the origins of life in Galveston, Texas, earlier this year. An edited and condensed version of that conversation follows.

QUANTA MAGAZINE: What have been the biggest accomplishments of researchers seeking to understand life’s origins? What questions remain to be solved?

DAVID DEAMER: We have really made progress since the 1950s. We have figured out that the first life originated at least 3.5 billion years ago, and my guess is that primitive life probably emerged as early as 4 billion years ago. We also know that certain meteorites contain the basic components of life. But we still don’t know how the first polymers were put together.

Scientists disagree over how to define life. NASA has come up with a working definition: an evolving system that can make more of itself. Is that sufficient?

Life resists a simple abstract definition. When I try to define life, I put together a set of a dozen properties that don’t fit anything not alive. A few of them are simple: reproduction, evolution, and metabolism.

Many scientists study individual steps in the emergence of life, such as how to make RNA. But you argue that life is a system, and it began as a system. Why?

DNA is the center of all life, but it can’t be considered alive even though it has all the information required to make a living thing. DNA cannot reproduce by itself. Put DNA in a test tube with water, and it just slowly breaks into different pieces. So right away, you see the limitation of thinking about single molecules as being alive.

Courtesy of David Deamer

Fatty molecules called phospholipids can spontaneously form convoluted membrane structures.

To get a bit of what we call growth, you have to add the subunits of DNA, an enzyme to replicate the DNA, and energy to power the reaction. Now we have molecules that can reproduce themselves if they have certain ingredients. Are they alive yet? The answer is still no, because sooner or later the subunits are used up and reproduction comes to a screeching halt. So how do we get to a system that’s really alive? That’s what we and others are trying to do. The only way we can think of is to put DNA into a membranous compartment.

Why are compartments so important?

A car doesn’t function unless you’ve enclosed it; you need to keep the pieces in place. For the origin of life, you can’t have evolution without isolated systems—compartments that are competing for energy and nutrients. It’s like giving chemists chemicals but no test tubes. You can’t do chemistry without a compartment. On the early Earth, each membrane was an experiment in life.

What do you think Earth looked like when life emerged?

There was a global ocean, probably salty, with volcanic landmasses resembling Hawaii or Iceland or even Olympus Mons on Mars. Precipitation on the islands produced freshwater pools that were heated to boiling by geothermal energy, then cooled to ambient temperature by runoff. Contemporary examples include the hydrothermal fields I have visited in Kamchatka, in Russia, and Bumpass Hell on Mount Lassen, in California, where we do field work.

Courtesy of David Deamer

Bumpass Hell, a hydrothermal field on the volcanic Mount Lassen in California.

Why would these pools have been a likely birthplace for life?

Organic compounds accumulated in the pools, washed there by precipitation that rained down on the volcanic landmasses. The pools went through wetting and drying cycles, forming a concentrated film of organic compounds on the rocks like the ring in a bathtub. Within that film, interesting things can happen. Lipids can self-assemble into membrane-like structures, and the subunits of RNA or other polymers join together to create long chains.

You’ve found that lipids can help form RNA. How does this work?

We have developed a method for joining together the individual subunits of RNA to make a long chain. We start with the molecules AMP, adenosine monophosphate, and UMP, uridine monophosphate, which are two of the building blocks of RNA. In water, the subunits simply dissolve and can’t form longer chains. We discovered that if you trap the AMP subunits between layers of lipids, the subunits line up. When you dry them, they form a polymer. The wet-dry cycle also creates lipid droplets that encapsulate the polymers.

Now we’re trying to recreate that process in the lab under the sort of conditions you’d find in a hydrothermal field. We use half-hour wet-dry cycles to simulate what happens at the edge of pools. We have shown we can make polymers ranging from 10 to over 100 units.

And you believe this is what happened on Earth?

We are testing the possibility that what we see in the lab can also unfold in a site that resembles early Earth, such as Bumpass Hell on Mount Lassen. My colleague Bruce Damer and I were up there last September, testing whether the hot gases coming out of a fumarole could drive the reaction that makes RNA polymers. The results are very preliminary and need to be repeated, but we did see evidence of polymers.

You likened the droplets to test tubes, with each being an experiment in life. What would qualify as a successful experiment?

Courtesy of David Deamer

Deamer proposes that biological molecules evolved in hydrothermal pools. Layers of lipids would build up on the edges of the pool, trapping chemicals and encouraging the growth of RNA (red lines). Lipid-bound droplets would then peel off from these layers, creating RNA-filled proto-cells.

The idea is that each [droplet] will enclose a mixture of random polymers. Rare protocells may house collections of polymers with specific functional properties. For example, some polymers might help stabilize the cell membrane, extending its lifespan. Others might make pores in the membrane, allowing nutrients to enter the cell. Still others might catalyze reactions, converting those nutrients into something the cell needs. These RNA-based enzymes are called ribozymes. We want to see if we can detect functional polymers among the trillions of random-sequence polymers we generate.

What would be the most exciting possible discovery in this system?

To get the thing to replicate would be a big deal. To do that, we need a ribozyme that makes our polymerization reaction go faster. But we have a long way to go before we can find that kind of ribozyme.

Once scientists are capable of making life in the lab, will we understand how life originated on Earth?

We’ll probably be able to make lab life, but I’m not sure we can claim that’s how life began. The life we’re trying to synthesize is going to be a very technical life, based in a lab with clean reagents and so forth. I’m not sure we can call that the origin of life until it becomes a self-growing system, until we put that system in an outside environment and watch it grow.

Although we will never know with certainty how life did begin, it seems eminently possible that we will understand how life can begin on any habitable planet, such as the early Earth and perhaps Mars.

This article was reprinted on TheAtlantic.com and BusinessInsider.com.

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  • Silly article. "We are just about to create life" articles come out at regular intervals, make a splash in the pop-press convincing low SEM savvy population that science has done the deed. Please define 'simple' life. What is simple about a single cell plant or animal other than it doesn't have other cells attached to it? Please describe the experiment (preferably electrical arcs striking a puddle of chemicals as these articles always propose) that will stack a simple protein. Please describe the demonstration experiment that will produce a self-replicating RNA molecule.

  • This was a great article. It was very interesting. One of the biggest issues is getting everyone to agree on what basic life is. Once that is done our efforts will be better focused on what we do not know and hopefully we will see more breakthroughs. Keep up the great work!

  • Interesting. I’ve seen the earlier work on membrane development, that RNA came before DNA, and perhaps it was the work of David Deamer. Life’s origin is one of the great mysteries of science. Once DNA is here, everything that happened in evolution is within its grasp – but where did it come from?

    The theory that the earliest form of life was based on chemosynthesis which evolved into photosynthesis holds merit but has not been proven. Science not only tells us what we know, but we should not forget that it tells us what we don’t know also.

  • Prime-ordial soup together with algae in volcanic environment starting with e.g. diatoms. before proteins ever existed – yes why not ?

  • If a scientist can make a living cell out of non-living components in his laboratory, does that prove or disprove the theory that life on earth was created by an intelligent entity?

  • Deamer's suggestion that membranes are essential to the formation of early life is not controversial but his description "Organic compounds accumulated in the pools, washed there by precipitation that rained down on the volcanic landmasses." begs the question where did the organic compounds come from? Given that the the Hadean atmosphere was mainly the result of out gassing of CO2, water vapour and small amounts of hydrogen that readily escape the Earths gravity.

    To make organics we need a continuous energy source and a catalyst, warm soupy pools just don't cut it. Are there any reference to his experiments?

    For a far more plausible and detailed exposition see Nick Lanes "The Vital Question".

  • A very interesting article. Dr. Deamer's research on the processes that led to life gives us a plausible scenario
    To comprehending the movement towards life on the early Earth. It offers a possible avenue to the enormous
    Mystery of the phenomenon of life. We must acknowledge that it is only a part of the puzzle, although an important one. We have discovered that the universe is made of atoms. And that while atoms have been called the building blocks of life, they are not like bricks. They are not inert for example, nor solid, nor subject
    To breaking down, in the ordinary sense. They vibrate and intermingle, creating new possibilities. These mysterious entities, enjoin us to ask the question, as Dr. Deamer has intimated, is life an inherent property of the Cosmos?

  • At the birth of life there was definitely a chemical reaction. The important property it had was that it was in a state of equilibrium and the thought that developed in maintaining this ensured it survival. The significance of the Le Chateliers's Principle in this whole process has never been recognised.

  • See, The Origin of Life Circus: A How to Make Life Extravaganza for conversations on origin of life with James Simons! as well as David Deamer, Jack Szostak, Dimitar Sasselov, Matthew Powner, Freeman Dyson, Carl Woese, Nigel Goldenfeld, Pier Luigi Luisi, Nick Lane, Steve Benner, Andrew Pohorille, Steen Rasmussen, Norm Packard, Michael Russell, Doron Lancet and more: http://www.amazon.com/The-Origin-Life-Circus-Extravaganza-ebook/dp/B01CPNHK1G

  • Given Deamer's background it would be natural for him to assume that DNA is the center of all life, but it isn't. What makes the difference between living and nonliving is the consumption of energy to fight back entropy. DNA could do nothing without energy being fed in for replication and protein synthesis. Life HAD to originate where geochemical systems could provide that energy in a constant usable form (no lightning allowed).

    I concur that people should read "The Vital Question" for a primer on a serious discussion of the origin of life and the complex cell. They might benefit from starting with this much shorter article which brings up many of the same issues but doesn't discuss them or the possible answers in the same depth as the book:

    http://www.biochemist.org/bio/03705/0006/037050006.pdf

    This hypothesis makes that simple cell an emergent property of wet rocky planets with copious carbon dioxide. It is the complex cell that is probably a lot rarer.

  • Good article–and the video! I didn't see it before the businessinsider.com reprint, which left out the video at least. Now that I know about Quanta Magazine, I'll keep an eye on it and see what other interesting investigative science articles are there or come along.
    But back to Deamer's work: Things have certainly at least advanced considerably since the Miller-Urey experiment of '52!

  • His experiments are similar to building a bird's nest. If a bird lands on it, it's "Look, I've created life!" Life is a virus that infects matter, instructing matter how to build a framework that best carries it in a certain environment. Protons, neutrons and electrons are not alive, although, that is what I'm made of. Amino acids, rocks and brains are all just basic particles arranged in a certain way, and their arrangement doesn't make these particles alive, life inhabits the construct separate from the construct. The bird builds a nest and then inhabits it. Life creates a framework of matter and inhabits it.
    This would imply that life came from space and landed on earth. But where did it come from? It had to be created at some point between the big bang and when it infected earth. Is it an intrinsic part of the universe?

  • John Roney may not mean to be spouting postmodern gibberish, but that is the impression his post is giving. Life is an emergent property of the universe only in that it is an emergent property of wet rocky planets like Earth. It is a result of the disequilibrium inherent in the geochemistry of planets or moons with active plate tectonics. Life is favored in that it generates entropy faster than any other process. The question isn't "what is life" but "what is living". :You really should read "The Vital Question" or at least the ten page article at the link I gave in my previous post here.

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