Freeman Dyson: Yes, "Garbage Bag World" Origins
Freeman Dyson: Yes, "Garbage Bag World" Origins
By Suzan Mazur
June 27, 2012
"Then after that came us -- stage six. That's the end of the Darwinian era, when cultural evolution replaces biological evolution as the main driving force. "Cultural" means that the big changes in living conditions are driven by humans spreading their technology and their ways of making a living, by learning from one another rather than breeding." -- Freeman Dyson, Eastover Farm
Several weeks ago the Lonsdale prize went to researchers who think first life was RNA, a replicating creature. So I rang up Freeman Dyson, emeritus professor at the Institute for Advanced Study, Princeton, to see if he still embraces the idea that original life was a "garbage bag world," a membranous creature with dirty water trapped inside that reproduced for a billion years or more with high rates of error before replicating.
Dyson does the math on this in his book, Origins of Life (2nd. ed.), based on Alexander Oparin's cell-first theory of metabolism. Dyson calls it his "toy boat model," calculated with pencil and paper, where thousands of molecular units make the leap from disorder to order with "reasonable probability."
During our phone conversation, Dyson told me that he does indeed still hold to his hypothesis and also still thinks RNA was a byproduct of that first creature's own metabolism, emerging as a parasite and eventual symbiotic partner. He says it doesn't make sense that original life copied itself without getting its act together first.
In his Origins book, Dyson also refers to Doron Lancet's work on defining metabolism, also based on Oparin's model, by computer simulations of origin of life, saying:
"Doron Lancet has tackled this problem by studying computer models of the evolution of molecular populations, which he calls replicative-homeostatic early assemblies (RHEA). In these models, metabolism is defined in a general way as the evolution of a population in which some of the molecules catalyze the synthesis of others. He finds conditions under which populations can evolve to a high and self-sustaining level of catalytic organization."
This prompted me to call Doron Lancet, a professor at Weizmann Institute, to see what his current thinking is. I reached Lancet at a conference in Stockholm. He had this to say about Freeman Dyson:
"He was my first inspiration. A chapter in his book, Infinite in All Directions, made me realize in the early 1990s that DNA/RNA was not necessarily the holy grail, and that there was an alternative in the form of molecular assemblies composed of mutually interacting simple molecules. The "Lipid World" model as a viable alternative to the "RNA World" would not have come to be without him."
Dyson envisions seven stages of life: (1) garbage bag stage -- metabolism without replication; (2) parasite emerges from garbage bag creature, parasite can replicate but not metabolize -- "zooms around" cells as viruses in packages; (3) collaboration of metabolic and parasitic creatures, RNA invention of "most mysterious" ribosome; (4) coupling of metabolic and RNA worlds (modern cell), two billion years of speciation and sex, beginning of Darwinian era; (5) multicellular organisms; (6) "us" and end of Darwinian era with cultural evolution replacing biological evolution; (7) whatever happens next.
Freeman Dyson describes himself professionally as a mathematician. He is recognized as one of the architects of quantum electrodynamics as well as one of the most provocative public intellectuals. As a scientist he has not needed a PhD, his BA in math from Cambridge has been more than enough. He now holds 21 honorary degrees.
Dyson's ability to find music in problems may reflect on his father having been a composer. As the story goes, as a teenager he, young Freeman, dealt with the challenge of reading Vinogradov's An introduction to the theory of numbers by learning Russian and then translated Vinogradov's text into English.
Freeman Dyson is a Fellow of the Royal Society, National Academy of Sciences, and Paris Academy of Sciences, and the receipient of numerous awards, among them: Lorentz Medal (Royal Netherlands Academy of Sciences); Hughes Medal (Royal Society); Max Plank Medal (German Physical Society); Enrico Fermi Award (US Department of Energy); Lewis Thomas Prize (Scientist as Poet, 1996), Templeton Prize (2000).
Dyson's books include: Disturbing the Universe, Weapons and Hope, Origins of LIfe, Infinite in all Directions, From Eros to Gaia, Imagined Worlds; The Sun, the Genome and the Internet, A Many Colored Glass: Reflections of Life in the Universe.
Aside from his affiliation with the Institute for Advanced Study, he serves on the board of trustees and is a past president of the Space Studies Institute, founded by the late Gerard O'Neill.Dyson is also a member of Jason, a defense advisory group of scientists.
My interview with Freeman Dyson follows.
Suzan Mazur: Has your thinking about origin of life changed significantly since the second edition of your book Origins of Life 13 years ago? And do you still say everyone is equally ignorant about origin of life?
Freeman Dyson: Yes, I would still say that. We've learned a certain amount since then but the basic mystery remains. We don't have a clearly defined chemical path from a mixture of garbage to an organized cell. That's what we somehow have to discover. The main difference between my thinking about things then and now is that now we firmly understand that there was an RNA world. The evidence for the preponderance of RNA at some stage has become stronger. And, of course, we know about various kinds of RNA operating in living cells today.
Suzan Mazur: Is your hypothesis still that the original living creatures were cells with a metabolic apparatus but without a genetic apparatus -- this was not an RNA world -- and that cells reproduced with high rates of error for perhaps at least a billion or more years before they began replicating? And that the replicator was a parasite. You say in your book that by metabolism you mean "what the Germans mean by Stoffwechsel with no restriction to genetically directed processes."
Freeman Dyson: Yes, I would still say that there must have been a purely metabolic phase. My thinking is that there were three origins: the original metabolic life, followed by parasitic RNA life, and then finally protein life. There is evidence now that RNA, the replicating stage, probably started a little earlier.
Suzan Mazur: In your book you have a section on Oparin's theory of cells first, enzymes second and genes third. And of Doron Lancet's work, a proponent of Oparin's theory. Do you continue to be keen on Lancet's "Lipid World" regarding origin of life? And if so, why?
Freeman Dyson: Yes, although I don't know what Doron's been doing recently.
Suzan Mazur: You describe Lancet's idea in your book by saying, "Life began with little bags, the precursors of cells, enclosing small volumes of dirty water containing miscellaneous garbage." Can you say more?
Freeman Dyson: Yes, that certainly I would agree with Certainly lipids are the most likely candidates. It would be the first stage of developing life. These little bags which gradually become cells. I would say that still looks very plausible. But I don't know what further research Doron has done in the last 10 years.
[Note: Doron Lancet has emailed me saying: "Freeman Dyson's mention of my work relates to our basic idea that life began with much smaller and simpler molecules than RNA…Dyson was attracted to this idea (which he jokingly, but lovingly called the garbage bag model) because it constituted a quantitative, physicochemically rigorous model for self-replicating entities that could jump-start life without resorting to long templating biopolymers such as RNA…
What is so nice about such spontaneously accreting building blocks is that (1) they can be simpler than nucleotides, the building blocks of RNA, e.g., fatty acids (simple lipids) found in meteorites as per Dave Deamer's papers and (2) they come in thousands of different kinds, allowing the assembly to be "interesting" compositionally and chemically, hence jump-start more complex subsequent chemistries, including the formation of simple polymer chains, as claimed by both Dyson and Deamer [Deamer was on sabbatical in Lancet's lab 10 years ago.]..."
In short, we claim (as Dyson and Deamer do) that RNA is a result, a consequence of simpler chemistry, not a necessary early "moving force". What is good about our model is that it is not hand-waving. We simulate in the computer accurate chemical progressions that mimic the process described for the appearance of RNA-like templating molecules."]
Suzan Mazur: What do you think of the Lonsdale origin of life prize going to RNA World proponents John Sutherland and Matthew Powner? The search was for a proposal that identified life as "a self-sustaining chemical system capable of undergoing Darwinian evolution."
Freeman Dyson: I think I would not make any comment about that. I don't know anything about the details.
[Note: Doron Lancet says further: "RNA World and Lipid World are considered by many as competing models for life's origin. John Sutherland partially alleviated some of the most bitter criticisms against the RNA World by showing that the small molecular building blocks of the RNA chain may be formed prebiotically. This is still far from saying it wins as a full-fledged model for the origin of life. . . . There are many open questions that continue to be debated in the field regarding formation of chains, the capacity of such chains to replicate and more."]
Suzan Mazur: So you still think it was metabolic and cell first.
Freeman Dyson: Yes, the RNA world was clearly a stage, but I would call that stage 2 not stage 1.
Suzan Mazur: You say the time frame may be a little sooner for the RNA World, how much sooner would you say?
Freeman Dyson: Completely unknown. We have no idea really how fast things went.
Suzan Mazur: How many camps would you say there are there regarding the origin of life question?
Freeman Dyson: I haven't really been following all the discussions.
Suzan Mazur: Are you familiar with the ideas of Adrian Bejan that origin of life is 100% physics and that both animate and inanimate are live systems, i.e., organized flows of matter and energy?
Freeman Dyson: I would strongly disagree. It's essentially a problem of chemistry.
Suzan Mazur: Who else's origin of life work on this subject do you like?
Freeman Dyson: I haven't really been following it, so it's hard to answer. But it obviously is a problem of chemistry, and the chemists have not made much progress as far as I know.
Suzan Mazur: What kind of experiments should they be doing?
Freeman Dyson: Little tiny microdroplets experiments. Chemistry now is getting the tools to do that. Getting accustomed to working with nanograms of material. You want to have experiments with big numbers of little droplets with various mixtures of stuff and seeing what happens
Suzan Mazur: You draw an analogy in your book between origin of life and the origin of body plans half a billion years ago, a "sudden efflorescence of elaborate body plans," during the Cambrian explosion Have you had further thoughts about this in light of the "evo-devo revolution"? Did form come first or did form arise from genetic programs?
Freeman Dyson: I haven't thought about that recently. Clearly we are understanding much more about embryonic development. The thing I'm most excited about is HAR1 and HAR2 discoveries of David Haussler, but of course, that's much later in history.
Suzan Mazur: Do you think form came first?
Freeman Dyson: By the time of the Cambrian explosion is very late in the history of life and genetics had become very powerful. But, of course, we have no idea what happened in detail.
Suzan Mazur: How soon do you think we'll get to the bottom of things regarding origin of life, i.e., make the breakthrough?
Freeman Dyson: Give it a hundred years, perhaps, but I don't think my prediction is worth anything. It all depends on what nature says, because nature is always surprising us. And probably in this case too.
Suzan Mazur: A hundred years. You think it's going to take that long?
Freeman Dyson: Well I would call that short.
Suzan Mazur: You've been criticized for making blase' comments regarding genetic engineering, in light of what we now know about cell dynamics and jumps. Would you comment?
Freeman Dyson: We are all aware of the dangers. That's nothing new. My feeling is there is no safe path. Trying to put a stop to biology is really not going to remove the dangers. Might as well let it go ahead. I'm quite aware of the risks in going ahead but the risks in not going ahead are probably just as big.
Suzan Mazur: You've opposed recent wars. Do you ever have regrets about your comments about the atomic bomb and Hiroshima or of having served as a military adviser?
Freeman Dyson: Oh not at all. I still am a military adviser. I'm very happy with that. The military needs people from the outside to give them advice and to bring them into contact with the outside world
Suzan Mazur: You're obviously advising them against wars.
Freeman Dyson: Well they don't ask me when they're starting a war of course. I only advise them about details. We don't expect to be asked whether or not to start a war.
Suzan Mazur: You now consider yourself a natural scientist?
Freeman Dyson: I'm a mathematician basically. What I do is look around for problems where I can find useful applications for mathematics. All I do really is the math and other people have the ideas.
Suzan Mazur: Would you like to comment further about origin of life?
Freeman Dyson: I don't think so. I've been interested just now in the Prisoner's Dilemma which is a totally different problem that has to do with the evolution of altruism. A very important problem but nothing to do with origin of life. I just published a piece in the National Academy of Sciences about the Prisoner's Dilemma.
Suzan Mazur: I notice in your book that you have a section on Lynn Margulis, who you describe as one of the "illustrious predecessors," particularly for her work on symbiosis, saying that "she set the style" in which you came to think about early evolution. Do you miss her?
Freeman Dyson: Yes. Oh very much, yes.
There's another lady who I admire very much -- Ursula Goodenough. Do you know her?
Suzan Mazur: I don't.
Freeman Dyson: She's also a biologist who does very beautiful things. She's an expert on speciation, the way new species are developed. Anyway I recommend her, she's just about as good as Lynn Margulis.
Suzan Mazur: That's quite an endorsement.
I also wanted to ask you about the piece that Richard Lewontin wrote for New York Review of Books in which he said that Charles Darwin intended natural selection as a metaphor, not to be taken literally by generations of scientists. Do you have any comment about that?
Freeman Dyson: No I didn't know about it at all. It doesn't sound sensible.
Suzan Mazur is the author of The Altenberg 16: An Exposé of the Evolution Industry. Her interest in evolution began with a flight from Nairobi into Olduvai Gorge to interview the late paleoanthropologist Mary Leakey. Because of ideological struggles, the Kenyan-Tanzanian border was closed, and Leakey was the only reason authorities in Dar es Salaam agreed to give landing clearance. The meeting followed discovery by Leakey and her team of the 3.6 million-year-old hominid footprints at Laetoli. Suzan Mazur's reports have since appeared in the Financial Times, The Economist, Forbes, Newsday, Philadelphia Inquirer, Archaeology, Connoisseur, Omni and others, as well as on PBS, CBC and MBC. She has been a guest on McLaughlin, Charlie Rose and various Fox Television News programs. Email: email@example.com