Creating life in the lab: Can it really be done? with Steven Benner

Our good evening, ladies and gentlemen. Having shown you a few photographs of Steve Benner in his lab, it's now my pleasure to introduce the man in the flesh. So, my name is Paul Davies. I'm director of the Beyond Center for Fundamental Concepts in Science, and as many of you know, our motto is "Confronting the Big Questions." And the sort of big questions we like to confront, I often say, are the things you love to talk about over dinner parties. Things like, "How did the universe come to exist?" "How did life come to exist?" "Is time travel possible?" "What is the destiny of mankind?" "Where do the laws of physics come from?" All that sort of stuff.

And the question about how did life begin is, of course, one of the most fundamental that people can ask. For thousands of years, human beings have dreamed about being able to create life. The physicist Richard Feynman famously wrote, "What I cannot create, I do not understand." Creating life might be a dream, but people also fear its consequences, as Mary Shelley's famous story of Dr. Frankenstein's monster so graphically illustrated.

Today, we no longer believe that life is some sort of magic matter, but rather an exquisitely fine-tuned and complex physical and chemical system that can be understood by the scientific method. But still, the prospect of designing and creating new forms of life remains both thrilling and, in some ways, troubling. And no person is better qualified to address this topic than tonight's speaker, who's come closest to attaining that goal.

Steven Benner established the Foundation for Applied Molecular Evolution in Gainesville, Florida, after a distinguished career in academia. He has a PhD from Harvard University in chemistry. I was tempted to say he's not merely a chemist, but some of my best friends are chemists. As Stevie's is much more than a chemist, I think his work has impacted fields with tongue-twisting names like paleogenetics, evolutionary bioinformatics, planetary biology, and astrobiology, but especially the burgeoning new field of synthetic biology. His life, his book, "Life, the Universe, and the Scientific Method," takes a penetrating look at the problem of "What is life?" and "How would you know if you found it?" for example, on Mars. Copies of the book will be for sale after the lecture, and Dr. Benner has kindly agreed to sign copies.

One last announcement: Please turn off your cell phones. And ladies and gentlemen, now join me in welcoming the 2004 Beyond and Your Lecturer, Dr. Steven Benner.

Surprised to see so many people here on a Friday evening. It speaks well, I guess, of the intellectual atmosphere in Tempe, Arizona, and surrounding communities. I'm hoping I'm not going to just disappoint. How are we doing? Can people hear me? Would you like it louder? All right, excellent.

So, what is life? And the problem is, my next slide is going to be perhaps... no, perhaps it won't work at all. Hmm. No. But it seems like this is the kind of question that should be approachable using what we teach in middle school as the scientific method, right? Because after all, if we're going to go search for life on Mars, should we not know what we're going to be searching for? And it seems to me, therefore, that the scientific method should be brought to bear to answer the question, "What is life?"

Now, who here did a science fair project when they were in middle school? Raise their hand. Who enjoyed it? See, the problem is that, you know, we're not going to get a lot of information for this kind of a big question from the science fair middle school paradigm. Because, you know, if you're in, in, in this game, what you are supposed to do is ask the question, then you do like background research, and then you construct hypotheses which you test with an experiment, a deathly designed experiment. So even a negative result tells you something informative. You analyze results, draw conclusions, and if the hypothesis is true or partly true, you're supposed to report the results. And if not, you're supposed to go back and think and try again. No, that's fine. But it's a skill. There's no question that it's like playing chords on a piano, right? If you're going to try to learn how to play the piano, or if you're trying to learn how to do science, presumably you have to be able to do something like this. But it really doesn't do much for these big questions like, "What is life?" or "How did life originate?" or "How might we recognize life if we were to encounter it on Mars?"

And so I thought I would sort of weave these two questions together tonight with sort of a sort of semi-philosophical look at what we do as scientists to try to ask some of these big questions. And of course, the very first thing that we do is we observe. And this is certainly true for our friend the biologist, who is observing a moose. That it was a biological living entity. And there's no question that he is going to consider that moose the subject matter of his discipline. Certainly, a moose is within biology.

Of course, one of the problems already is that you have two kinds of biology. There's the so-called natural history biology, which means that you observe biology, you observe animals, you observe moose. Maybe you might look at the fossils, and somehow you, maybe you might probe them a little bit. So a good friend of mine, Gary Bulloughski, would go out into the Montana Plateau, pick up moose droppings, figure out what the moose had been eating, and then make an energy balance, trying to predict how the moose would be, you know, walking around next week or the next month in response to environmental stress.

Of course, the biologist has this choice. He can also do something different. He can shoot the moose, right? This is why this is a Jake Fuller cartoon of decisions that biologists make. Because if you kill the living things, you can analyze its pieces. You might be able to go further. Of course, the natural historian biologist doesn't think this is biology any longer at all, right? Of course, there is no love lost between these people. Harvard's biology department divided into two. There's the two groups of people: those who observe the moose and the people who shot the moose could not really get along. But the bottom line is that observation alone in biology has not turned out to be particularly productive in going past the sort of bulk descriptive, "Describe the moose." You can describe what he eats, what he does, but and it doesn't really answer the "why" of the moose.

So there's analysis. Okay. And so the analysis, of course, starts with, unfortunately, killing the the organism. It is then dissected. The dissection is to the level of the organ, and then, of course, the cell. But eventually, to the level of the molecule. We have, of course, the historical beginnings of analysis in modern biology, where they're trying to look at the Mastodon. Otis was to do with the pieces. But at some point, you get all the way down to molecular representations of what is in the moose or the Mastodon. In fact, you're looking at this here. This is a structure of something that you have in your bodies. It's called the ribosome. It is actually the molecular machine that makes proteins. You're making proteins all the time from the food that you are presently digested. Of course, that's you ate. Protein is protein is being broken down into amino acids, and they're being reassembled into new proteins. Your proteins, not the Mastodon's that you had for dinner.

And so the bottom line here is, at some point, analysis gets to the point where you're actually looking at individual atoms. And that's where these little bumps are. Each one is a different atom. And that's the section roughly to the level of the molecular system, which makes most biology today associated with a chemical description. Almost everybody will talk about metabolism. They'll talk about the chemistry of metabolism. You talk about vitamins. They'll talk about the molecules that are vitamins. You talk about genetics. They talk about the DNA that's part of genetics. And so that's a very popular area because it's also an explanation for why we do not find aliens among us. Because as any alien will tell you, if you a scientist near an alien, what does the scientist want to do to the alien? They want to dissect them. And there's 12 Steven Spielberg movies embedded in that observation.

Great. Now, keep in mind that analysis plus observation together has been quite productive. We do have theories for life. And I've represented three of them here by the appropriate statues. There's a cell theory of life, roughly 1838. This is a guy named Schwann, who is a man who said, "Hey, maybe actually it's kind of amusing." If you read his original papers, he's trying to unify botany and zoology, noticing that both animals and plants have something in common, that is, that they are made up of cells. And so this is the cell theory of life. And one of the leading journals in modern biological science is called Cell, simply Cell.

Of course, this is Charles Darwin as a young man, much more handsome than those pictures that you see of him as an old man. And he has evolutionary theory, which is, of course, a very central theory in biology as well. Of course, eventually, here's Watson and Crick talking about the gene theory. There is their famous structure of DNA. I've expanded some of the DNA into chemical structures here. And so we do actually have, from analysis, we have from observation, these theories exist. And people talk about them. People teach them in classes. Um, and so you can come up with sort of this idea that sort of combines them. If this is actually a definition that was suggested by none other than Carl Sagan, which is being used, among other things, as NASA goes out and looks for life in the cosmos. That life is a self-sustaining chemical system capable of Darwinian evolution.

What we mean by self-sustaining is not that you can live without anybody else around you. You have to eat things, but you were able to go out and get your own food, right? And of course, capable of Darwinian evolution. Darwinian evolution is a big term with lots of baggage. It means being able to have children. The children are mutants, sometimes in some detail, actually many people think they always are, but they say they are always. And then, of course, the having a survival of the fittest and natural selection to operate on it. That's all embedded in those two words.

Well, excellent. So Watson-Crick. Tomorrow, I'm going to be this dangerously close to chemistry, but I want to try to help you out here. There you go. I mean, Watson-Crick model for DNA. Almost everybody saw this. It's something put in there. Okay. So who saw this at some point in their high school education? Raise your hand. You see, now that's a good response. That shows the robustness of the American education system. Fair enough. A pairs with T, G pairs with C in this double helix, where replication and veneers the double helix over here. Replication involves separating the strands and then making a complementary strand by putting in G opposite C and T opposite A and A opposite T and so on. You get two copies of the same thing. Occasionally, there's a mistake. That's the mutation, which, if it's not repaired, ends up being the the playground of evolution. But it's a relatively straightforward model, and it's actually 60 years old, roughly.

So now you can ask the question, so how has observation and analysis and these theories of biology served us when we actually needed to do something with them, like look for life on an alien planet? In this particular case, Mars. Now, in 1976, about 40 years ago, Viking mission actually was to duplicate missions. Landed at two separate sites on the surface of Mars. They were at the time, roughly, the most expensive experiment, scientific experiments that were ever done. And they carried with them life detection experiments. And in fact, there were three of them.

And you can think about this for a minute, because the first one, they were going to sprinkle food on the surface of Mars and see if carbon dioxide is emitted. And that's the purple line. Um, second, they were going to water the surface of Mars and see if oxygen was released. Now, the third thing they were going to do is they were going to put carbon dioxide on the surface, in the atmosphere above the surface of Mars, a little bit of carbon monoxide, trying to reproduce the actual atmosphere of Mars. They were going to see a carbon entered the ground. It's fixed, as we like to say. These experiments actually are not applying any of those three theories of life that I've told you about. They don't apply a cell theory. They don't apply an evolutionary theory. They don't even apply a gene theory of life. What they are doing, actually, is constructively applying what we would call a metabolism theory of life.

And the reason why is because if I go out and feed you some food, you will release carbon dioxide. If I water the ground outside where something is growing, photosynthesis will take place, and they will release oxygen. And of course, tearing organisms at the bottom of the food chain will actually fix carbon dioxide. That's how the plants get their carbon, right? They have carbon dioxide in the atmosphere, which they suck up and make in the plant. No. You can look at that. You can say this is what we call Earth-centric or Earth-eccentric, right? We are making the design, the tests, looking for life on Mars. We're designing it for expecting the life on Mars to be very much like the life on Earth.

And for those of you who are not aware of these results, all three tests for life on Mars were positive. 1976. This is Gil Levin. He's the man who designed the Raible release experiment. He will still tell you, he's still living, he will still tell you that he is the man who discovered life on Mars. The conclusion, therefore, all the CO2 was released when they sprinkled food on, the oxygen was released when they watered the surface of Mars, and carbon dioxide was fixed when they put radioactive carbon on the on the surface. The conclusion: life is present. If you're going to interpret these tests on their own terms, there's life on Mars.

And so the question you probably are wondering is, "Why the hell haven't I even told about this?" Right? Who thinks that there is life on Mars? Raise your hand. Who's Gil Levin in the audience? I don't. Sam, right? Yes. Yes, absolutely. He's got great associations. So the bottom line is that those experiments were tested. So the question is, why haven't you heard about it? Why I get many more hands up when I say, "Who's seen the structure?" you know, double helix, and I get by having somebody who's heard that these three tests for positive on Mars? The reason for this is because they did another experiment, all right? It took a little while. This is a gas chromatography mass spectrometer. For those of you who are in the business, you know exactly what this guy does. They scooped up a little bit of Martian soil, they entered it into a cup, they heated it up to various degrees of temperature, and what they're looking for is gas coming out, which they flow into hydrogen tube, and then they have a palladium separator and all the rest of it. But what they're looking for is reduced organic molecules. Oh, like glucose or its products. If I heat glucose up to 400 degrees, I get something off. For protein, if I heat protein up to 400 degrees, I'll get organic comments off. What did they find? Well, they found nothing. They found no organics. All right.

So we have three positive tests, our metabolism, and now we've got one test on the other side. So there's no organic model. So no one said anything about an organic molecule theory of life. But about the evolutionary theory of life, the cell theory of life, a genetic theory of life, but now we know that they are operationally constructively using the organic or reduced carbon theory of life. And we know it trumps actually a metabolism theory of life because if you got three positive tests for metabolism and one sign there's no reduced organic, no reduced organic wins. So you're learning something about how these scientists are thinking.

But here's even worse. This minute, the minute, the minute they decided that there was no life on Mars, there could be no life on Mars because there was no reduced organic compound. What did they do? Well, the minute that they decided that there was no life on Mars by the GC mass spec, they went back and found explanations for how you could get three positive metabolic results out of the metabolism test. And of course, the first thing they noticed was a sort of Venn diagram, which is the red circle is all systems that transform organic compounds, and the blue circle is all living systems, including you. But of course, outside the living system circle, but still within the transforming organic species circle, is your car. And no one thinks your car is alive. So that was saying that, okay, as soon as the community decided that they needed explanations to find non-life explanation for the signs of Martian life, they found them. And they were found them within minutes, days, not weeks, months, or years after the results came in. Now, you could have asked, "How come they didn't think of these before?" But that's a that's a separate question, which I will entertain in the question-answer card.

Well, this is water, by the way, just for those of you who want to know what they think happened. Are they, what they thought happened. This is continuing to evolve. Water is, hmm, H2O. Many people know that ultraviolet light comes to the surface of Mars much more intensely than on Earth because it does not have an ozone shield like the Earth has. It will split water into an H zero and an H O and an H dot. An H dot. These are two hydrogen atoms, each with their electrons. And then what happens is these two H dots can recombine. The hydrogen and hydrogen that may escape into space, leaving behind hydrogen peroxide, which is a reactive species, is an oxidizing species. It's something you might have in your bathroom or in a mouthwash, you know, where you swish your mouth with, you know, bubbles of oxygen. And of course, this is a reasonably powerful oxidant, or it can be. And so the argument was that this is what is actually oxidizing the food to make carbon dioxide, not metabolism. This is an inorganic oxidation process, getting its energy ultimately from the ultraviolet light that is coming from the Sun to Mars.

So there goes poor Gil Levin's tests. There is the food that they sprinkled. They put a couple of amino acids like glycine, a sugar like lactic, a glycolic acid, or lactic acid is not quite sugars, but in point of fact, all of these are oxidized by hydrogen peroxide in the presence of iron, by the way. This is a reaction that was known in 1900, discovered by the German chemist, Rufe. It's called the Rufe-Feld or the Rufe degradation. It's well-known species. Iron is the catalyst. Mars is the red planet, and it's red, presumably because of iron in the surface. So the science is at. And by the way, just for the record, you know, adding water is one of the ways that was argued to activate the hydrogen peroxide that's left behind. Ultraviolet light was being used as an argument as how the carbon dioxide was fixed.

So I don't want to need to go through the details. I certainly don't want you to walk out the door remembering the details. All that you should know is that the minute you had a theory, the reduced carbon theory, with a result, a gas chromatography mass spectrometer instrument trumps the metabolism. Metabolism theory folded. And immediately people found ways of actually explaining those results. And I don't dare go much farther than to say results meaning what the culture needs them to mean. That's sort of how it happened.

So the community was despondent. Okay, life was not likely to be present on Mars. Um, actually, this is, I should say, this book that Paul mentioned, this out in the lobby, is we got the Gainesville Sun political cartoonists to do cartoons for us. I must confess, at all I say was that the community was despondent. Before I know it, Jake Fuller has generated this hour, nice Martian is holding something called the McKay report. In 1996, the McKay report came out. But cheer up, the despondent scientists who were unhappy that they were not going to go find life on Mars. And what was in the McKay report? Well, he actually, by the way, in case you didn't know, have pieces of Mars on Earth. What happens is something slammed into Mars, ejects rocks. Some of them are ejected with enough speed to reach escape velocity, and then they travel around the solar system for a little while, and some of them land in Antarctica. And then you go down and scoop them off the ice. Does anything that's on the top of ice is likely to have fallen in. A small fraction of the meteorites, as you find, where explained as Martian derived. And and there will people look at atmospheric composition in those shot glasses and them Marshall made using these type of things. This is Allan Hills 84001. It's a meteorite from Mars. Dave McKay looked at it closely, and what he saw were cells.

How are you getting somewhere, right? We do at least have a cell theory of life. Yes. And so now that trumps the organic theory, right? Something was wrong with a GC mass spec. Actually, it turned out that there was an entirely separate interpretation for why that instrument did not find sure. Right. Now, Gil's pretty happy, right? Because after all, now what you're saying is a strong theory of life. You're absolutely observing cells. So the cell theory of life trumps the carbon theory of life, which of course trumps the metabolism theory of light. And so in 1996, Bill Clinton went on television, like if you want to see the clip, you can actually see it in the movie Contact, where the Carl Sagan excerpted Bill Clinton's discussion of the discovery of maybe life on Mars into the the discovery, of course, by Jodie Foster of extraterrestrial intelligence by their radio signals, for those of you who have seen the movie.

So no man. So I'm now wearing it. What I'm doing here is we're being sort of anthropologists of science, right? We're looking at the scientists and we're trying to make the distinction between what scientists say they believe and what they constructively believe. And remember, a constructive belief is driven from an actual belief because you act on her. So who believes here that quantum mechanics is true? Raise their hand. Yeah. Now, who is for whom is that a constructive belief? Like, what did you do today that actually required that you believe that quantum mechanics was correct? Nothing. I mean, even Paul, you didn't do anything today that required to be correct. Well, maybe you did. So, so, so you're looking at the scientists and saying what they do.

Now, for those of you who are students in the room, especially, what did I forget to put on this picture? A scale bar. Thank you. You're not a student. Absolutely. This is microscopy 101. What we forgot to put on that picture is a scale bar. Um, and so I will do now here. That scale bar is roughly 1 micrometer, 10 to the minus 6 meters. There's a meter, or a millionth of a meter. And so there's this size of an E. coli, a typical bacterial cell, given that scale bar. And people look at that and all of a sudden they said that these cells are too small to be life. Now, you know, I don't know if that was a very persuasive argument. Everybody was a cell biologist, but you know, the only correct response is, "What makes you think life cells on Mars have the same constraints that cells on Earth have?" Right? So you say, "Too small." Too small? What? Well, a presumed volume needed for a presumed set of components. Well, what could those possibly be? Well, there was an answer to that question when it was raised. And the answer is, there's that ribosome again. That's that ribosome I showed you a few slides earlier, which is the machine that you had to make proteins. There's the ribosome, the machine. And turn life that makes proteins. If I scale it down to here, it's roughly that big, which is roughly the width of that cell. And so the argument is that this cell is too small to be life.

Now, you know, I try to get the students to write out clean Aristotelian syllogisms. And so you, when you do so, you are no notice that you miss a premise, right? So if you say, "The cell is too small for a ribosome, therefore the cell is too small for life," you're missing a premise, right? Because somewhere is tucked in there, there's got to be a premise sign that proteins, which are what's made by the ribosome, are required for life, right? So maybe the cell is too small for ribosomes. Ribosomes are required to make proteins. Proteins are required for life. Therefore, the cell is too small for life. But you can't, you know, just hum the words to that. You got to actually say it all the way out. Because the question is big. Who is the third person who talked about the protein theory of life? Right? We've talked about the cell theory of life, we talked about the genetic theory of life, we talked about the evolutionary theory of life, we talked about the metabolism theory of life, we talked about the reduced carbon theory of life. We talked about the cell came back and trumped the metabolism. And now we're saying, "Ah, life requires proteins."

There's a problem with that. Um, and that problem is actually captured in the two colors of that ribosome, okay? The two colors of that problem. I'm now spelling this out for you. We might do some logic. Proteins are made by a ribosome on Earth today. Today, the information, by the way, in DNA is used to make an RNA molecule, catalyzing the in carrying the information from the DNA. Then RNA directs the ribosome to make proteins. Of course, presumably, life had to start sometime. And you know, if you got a system which requires DNA and a ribosome and an RNA molecule carrying information, that's a pretty complex system. And so it suffers from this question as to how the system gets started. Like, what are the odds that a DNA molecule emerged from Darwin's warm little pond? That's pretty low. What's the odds that a ribosome did at the same time, as well as all the translation machinery? This is what my creationist friends call the irreducible complexity problem, right? You just can't get it started because there's just too much.

And so, but never mind. The bottom line is it turns out that the ribosome, which we understand the structure by analysis, is in fact, it is the machine that makes proteins. But it's turned out that it's not made of proteins, mostly. The red, orangey colors are proteins. That's our ER. Are actually RNA molecules. And the blue components are actually proteins slapped on the surface. So what this says, and by the way, where the tene is actually made is surrounded by RNA. It's the RNA part of the ribosome that makes the protein. So now all of a sudden, you say, "Well, if RNA is needed to make proteins, and RNA came before proteins, are you with me, right?" Hmm. And by the way, some people have taken the leap that is an early episode of life on Earth used RNA as the only encoded catalyst. At RNA, in the early life forms, did both genetics and metabolism. One molecule doing both. That's actually a nice way of solving the chicken and egg problem, because I, if proteins are needed to make RNA, and RNA is needed to make proteins, which comes first? Or the answer is, RNA comes first. And the ribosome contains the evidence of that, because in the ribosome is the machinery that makes proteins. Proteins before RNA.

Now, if you think about that for 30 seconds in context of your discussion of the Martian meteorite, right? We said that the meteorite was too small to hold ribosomes. But if ribosomes are needed to make proteins, and it's the RNA of the ribosomes that made proteins, and the RNA therefore came before proteins, the assumption then is that there was not only is it possible for life to have no proteins, but that the earlier versions of life on Earth were organisms, RNA organisms, that did not use proteins at all. Well, you don't have to walk with me through this. By the way, just for those of you who are into vitamins, a lot of the vitamins that you either, in fact, cofactors that have a piece of RNA. And the argument has been, it's left over from a time on Earth where all the catalysts, all the metabolism that you did, was catalyzed by RNA species. So if you go out, for example, and buy yourself a vitamin with a pantothenic acid in it, many of you do, that's part of a cofactor that has an RNA piece. If you go in and buy something which is a part of coenzyme A, it's an RNA piece. ATP, the energy matter of life, has an RNA piece. The reaction can go just as well without the RNA piece. So the argument is that these are vestiges, as were molecular pandas thumb, of a time where your ancestors, life on Earth, did everything that life needed to do without proteins. In is built into the historical analysis.

So now work with me here, okay? An ancestral form of life on Earth that used RNA as the only encoded biopolymer is, of course, a vestige of the thing that makes proteins. RNA before proteins means RNA without life, without proteins. Life with only RNA. So if the RNA part of the ribosome is the part that makes the proteins, therefore, we go, RNA became before proteins. Double or ago, life is possible without proteins, with RNA alone. By the way, just for the record, about 70% of the volume of a big micron cell, the ones that cell biologists are used to looking at, the ones the same cell biologists who think that the life that we see, the cells on Dave McKay's Allan Hills Martian meteorite, are too small to hold life. About 70% of the non-solvent volume of a bacteria living in your stomach is being used to make proteins. So if you can get rid of the need to make proteins, triple ergo, I went to slides. Life based on RNA alone can be much, much smaller. Can be in much, much smaller cells. In life that needs proteins. What triple ergo? Therefore, the Allan Hills structures are not too small to be life. They just have to be life without having this devote 70% of their volume to making proteins, which is what the E. coli living in your stomach are doing.

How we doing? So there you are. Back. We put the scale bar in there. The structures of Dave McKay. This cell, a modern bacterial typical cell, is largely because it has to make proteins, therefore has to have a lot of these. The argument: these cells are not too small to be life based on RNA only, a kind of life that we think was actually our own ancestor on Earth, and that's because they don't have to contain any of these guys because they don't need proteins. So keep in mind, we're constraining our prejudice of what life is. And of course, it's just for the record. If you go out and there into the galaxy and you ask, you know, if you actually do believe that there was a prebiotic world, at life at some point originated, this is like a Hitchhiker's Guide. You know, everybody agrees that this was a bad idea. But never mind. You make the RNA world. It then takes some time to invent the ribosome. Okay. The ribosome is eventually invented, and now you can start to have an RNA-protein world. And of course, at some point, intelligence is invented. And therefore, you can actually go back and use your RNA-protein like to explore the cosmos.

Well, what are you most likely to find? You're most likely to find life that contains proteins, like yourself. Are you most likely to find the most primitive form of life, which only had one biopolymer in it, RNA? And the answer to that is, it depends on how fast SAR is able to invent the ribosome. If it's slow to invent the ribosome, is it ribosome is difficult to invent? If it's difficult to invent the machine that makes proteins, you go out to the cosmos, you're gonna find life that uses only RNA, has its genetics and metabolism molecule. Of course, if ribosomes are invented quickly, then of course, early life is originated. And of course, you'll find mostly organisms that use proteins. And of course, if you believe that intelligence is fast or slow, people have different views on that. But if you think that intelligence is slow to invade, you'll mostly encounter on intelligent organisms. Whereas if intelligence is quickly an advantage, you'll find mostly intelligent organisms. So again, I happen to think it's a little bit of a trouble to invent this machine. Therefore, I would not be surprised if all of the life on Mars were not in fact RNA life.

So are you with me? By analysis, right? By dissecting the moose, by dissecting the Mastodon, we've come up with a ribosomal, an RNA molecule, a ribosome. It makes proteins. From that, we say RNA, which is the orange part, which actually makes the proteins, is more important for making proteins than the protein part. RNA came first, proteins came later. Therefore, this kind of structure is early. Proteins are late. Life is possible with this kind of structure only, and not with proteins being required.

Now, sadly, the Martian cells turned out to be mineral ridges. You turn the rock on its side, you look at a different way. And so the question of Martian life shifted back to the despondent side. But later, what good water was found on Mars. And of course, that's the water theory of life, where you have water, you have I mean, the water theory of life sort of trumps any other things. I mean, clearly this saw and so on. I mean, clearly the science is not supporting us as we would like, especially when we set out to seek weird life, right? Because we're constantly going back and forth and back and forth and back and forth. The science we're doing its job. You expect to converge on some sort of a solution. You haven't done them all, right? No problem.

But there's a third thing that we can do besides observation and analysis. We can do something called synthesis. Now, what synthesis is, is a way of assembling things. Let me put things together in pieces. We've already done, as I've explained, the sort of exploration as we try to find examples of alien life that helps us understand what life is. We can already do an examination of fossils and modern life to try to understand what simpler life might be. This is this indeed going backwards in time from the modern ribosomes, for example, to more ancient ribosomes. I won't talk today about any prebiotic chemistry where you try to get life out of, you know, prebiotic soup in the laboratory. But I'm going to talk now about the fourth approach, which is to actually try to construct life in the laboratory, right? As there's sort of a reason for this. And Feynman was already mentioned this evening, because if we truly understand what allows a system to sustain Darwinian evolution, we should be to make one of our own, right? If you're so smart, right? Do it. Right? If you understand this.

And this is, of course, a final remark that was already quoted. "What I cannot create, I do not understand." Another one of my favorite Feynman's quotes is, "People are easy to fool." And the easiest person to fool is yourself. Synthesis does a couple of things for you. One of the things it does is not only demonstrates that you understand something, but it prevents you from fooling yourself into thinking you can do something or from thinking you understand something when you don't. And that is a really important thing because, in my view, science is an intellectual activity that it embodies a mechanism that Vence the scientists from always reaching the conclusions that they set out to reach. I mean, most of the time we're gonna do that. There's nothing we can do about that. But what science does is has an experimental method or an observation that is something that every now and then, once in a blue moon, it's the scientists to agree that he was wrong at some point, or she was wrong at some point. So synthesis is a mechanism for preventing you from fooling yourself. If you're serious and adequate, you cannot fool yourself into thinking the opposite. If you try, the synthesis fails. And it fails in a way that that cannot be a boy.

My favorite example of this, and I really should not bring this up too often, right, right, keep in mind, is this Mars Climate Orbiter. Now, keep in mind that the human instinct, and this is true even if you're a human scientist, what do you do if the observation that you have made contradict your hypothesis? You don't discard the hypothesis, you discard the observation, right? And in some cases, by the way, that's entirely reasonable, right? Because if the spectrometer is broken and doesn't give you right the right answer because it's broken, you should discard that. I mean, this is the classic example as to know if what's all emeralds are greens. You just observe an emerald and you discover it's not in green. That does that violate the rule? Well, no, you observe it under ultraviolet light. Well, okay, I didn't mean all emeralds are green when you observe them under white light. So then you, somebody comes along and looks at it under white light, says it's not green. He has red-green color blindness. They say, "Okay, I didn't mean that way. All animals are green when observed in their eyes." This is the called Quine-Duhem paradox. It's the fact that you are always making inferences based on a lot of assumptions that you don't really think about all the time. And so a lot of times, you know, you maybe should be discarding the observation rather than the hypothesis. But that's not a good idea to do as a general rule.

And one of the classic examples is that the Mars Climate Orbiter, which is going out to Mars, where the guidance system hardware was operating under the English system, no, feet, pounds, this type of thing. The guidance system software was being in the metric system all the way out. If you read the mission logs, some people knew something was wrong. They were burning too much fuel to correct it. And and they were able to rationalize it away. And then of course, but some point, you're targeting this Grand Challenge. The synthesis is forcing these scientists across uncharted grounds. If you're wrong, the rocket crashes, and there's no way around them. And so synthesis is able to drive paradigm change in ways that an analysis cannot. Because as you are happily writing your grant applications, do easy hypotheses, ignoring data that contradicting them, and publishing the data to confirm them, right? If you're trying to do synthesis, it puts a wrap into it.

So what we'd like to say is that synthesis sets this Grand Challenges. This is also in biology. Now, this is where synthetic biology is. You set this Grand Challenge. You drag scientists, kicking and screaming, there. Jake has the scientists being dragged across uncharted territory where they're forced to solve unscripted questions, okay, unscripted problems, using available theory. When the theory is inadequate, the synthesis fails. And it fails in a way that that cannot be ignored. Therefore, synthesis drives discovery and paradigm changes in ways that observation and analysis not. And so now we're on to the next stage. Okay.

So we think we're smart. We think that RNA alone should support a self-sustaining chemical system capable of Darwinian evolution. That's a definition of life, right? And so we ought to be able to do it if that's all there is to it. So there is a Watson-Crick base pair. Who here has ever taken a course in organic chemistry? Raise their hand. Who liked the course? I say, "I did." Right. Watson-Crick base pairing is easy to understand. And I'll get it easier in the next slide for those of you who don't know chemistry. But basically, there's a big piece, two rings, and a small piece, one ring. Big pairs with small. That's one of the rules of complementarity. Well, then hydrogen bond donors, which I have in red, and pair with hydrogen-bond acceptors, I have in blue. So cytosine, the C in DNA, as a small thing with a donor, acceptor, acceptor, red, blue, blue, hydrogen bonding pattern, and it pairs with guanine, which is a big thing with a blue, red, red, hydrogen bonding pattern, acceptor, donor, donor. And for those of you are not chemists, let me see if I can go to this. We can go to that structure, which maybe puts that a little bit more clearly, right? It's putting together LEGO sets, right? We have a big Lego piece, a small Lego piece. The big Lego piece has prongs and holes. And C pairs with G because it's got a prong, hole, hole, complementary to the poll, prong, prong, right? And contrast T. Well, God didn't get it right. And God, even with adenine, forgot to put the prong on the bolo or Lego P. So you actually hold the A-T base pair together just with the top two hydrogen bonds. But that's a mistake that I assure you, we do not make in the laboratory as chemists. We will put that NH2 group back. But never mind.

One of the things that you've got is a problem here because if you think about this as for 30 seconds, we like the idea if we want to build our own Darwinian system from scratch to demonstrate understanding, of course, not because we want to take over the world like Mary Shelley was protagonist does. We like the idea that nucleic acids alone might be sufficient for Darwin, right? You liked because that means we just have to design the nucleic acids. You don't have to also design proteins. So it's half the work that way. We only need to design one biopolymer, not two, from scratch. There's a problem. People have tried this. I mean, people tried to take, you know, this relatively simple system, even missing why, actually, I put already the amino group back in for the chemists or in the audience. Um, people which actually tried to get good function out of this system, they've largely failed. Um, we say that RNA should be able to support catalysis and genetics, that is metabolism and inheritance without proteins. But it just has four building blocks. DNA, the same. So it's actually not so many. I mean, proteins have 20 different building blocks. They have all, of course, there's 20 kinds of stuff on them. And the more stuff, the more you can do with a protein. So it's not terrible surprising that proteins are much better at doing metabolism, much better doing structure, in some sense. And so our knit has much less to work with. And so one of the arguments why people have failed to actually get, I mean, if you know, you can say, "If I think that life originated by an RNA molecule crawling out of a test tube or crawling out of a prebiotic soup and asking me to dance," right? I ought to be able to do it in a laboratory, right? But people try and people fail. And it's not clear why. But one possibility of why is you only have four building blocks and not much stuff to work with. Those proteins got a lot of interesting chemical stuff.

So the goal now is to take this structure. We've got a hypothesis now. So I am back in secondary school, middle school science fairs, right? We have a hypothesis: If we add more building blocks to RNA and put more stuff on them, but the RNA will be a better able to support Darwinian evolution. Um, so the question is, are there any suggestions as to how to add more letters into the nucleic acid alphabet? Now, the people in the front row to answer that question, and I'm not going to get anybody to answer this question until I start putting this back there. The two rules in cartoon form: big pairs with small. God's mistake left out of prong on this one. We'll put it back in. But you'll notice that I have a red dot, I prong, and a red dot, I have a prong. A red dot, and a red dot. I have not even begun to consume all possible designs of all Lego blocks, right? It doesn't take much to say, "Okay, there's T, small dot, prong dot. C, prong dot dot." Complementary is a big thing, right? Dot, prong, prong, and wrong dot. Well, there's God's mistake. But I can also have a dot dot prong, which is complementary to a prong dot dot. I can make another piece of Lego brick, and they will fit together like this guy will fit together with this guy. This guy will fit together. This guy. This guy will fit together with this guy. Get Braille, right? You know, the--and all the ways you have dots and prongs on these things. So, and so, you know, I, it's great. We can also make up new letters: J, V, K, X, Z, P. And my favorite, S, B.

The bottom line is that you can do all these structures in principle. The chemistry is now that right there. You are again now with the chemistry. With instead of prongs and dots, we have, of course, actual atoms and hydrogen bonding groups. And so, yeah, if it's so simple, in fact, that's what the Watson-Crick theory is. It's a very simple model for how genetics works. We ought to be able to get DNA not with four letters in it, but twelve. Now, that's not quite 20, which is what proteins have, but it's more.

Um, and and and we could, with more stuff, we can do more useful things. So what we're going to now do is do a new kind of genetic system that is not found anywhere in the United States, or not that I know of. Uh, though Paul might have some disagreement with that. I mean, we, I mean, it's a fact, by the way. And and and and Paul's written extensively, and they say there could very well be life I'm about to discover under the carpet here, and not because we made it and put it there, right? But it could be there naturally, and all the tests that we would use to look for it would not have found it. This is a Carol Cleland shadow biosphere, right? Which to get you the willies, if you haven't gotten them already. A new kind of genetic system.

And just for the record, I won't go through this details. I certainly will not bore you. All those molecules have been made. Actually, Stefan Lutz here is from Emory College. He sees one, Emory University. He sees one of the compounds that he worked on, which is that one, I guess. Think that Trudy ate it, if I recall, for his par. Those days, he gave the chemistry seminar three o'clock this afternoon. So there you go. We made these molecules. We put them in double strands. Anne Wong, who provided from Georgia State, provided us with selenium, selenium nucleosides to help us solve a crystal structure. And it looks just like the big, small hydrogen bond donor, hydrogen bond acceptor, exactly the thing. But you say this happens to be the ZP pair. Chris Switzer has looked at the SB pair. And I won't go through all the details, but it really behaves like DNA. That's actually useful.

It turns out that if I have A-T and G-C base pairs, and I put them into your body, you've got lots of DNA and lots of RNA with A-T or you G and C. And so almost all the nucleic acids in your body will interfere with DNA that you put in, right? And so we have a very common thing. What you want to do is detect nucleic acids in your body. Why? Well, because unwanted nucleic acid is what an infectious disease is, right? If you have an infection from HIV, disease comes from the unwanted disease HIV nucleic acids. Same thing with anything. So, so very often, we would like to do something called a beacon, which I'll describe briefly. It has a fluorescent molecule, but it's got this little hairpin structure. And because it has the hairpin structure, the fluorescent compound is next to a quencher. There it is, sort of in more double-helix form. So being the floor next to the quencher, the fluorescence is not displayed because any time the fluorescence tries to get started, it's quenched by the quencher. But if you have DNA here and you make a loop, say with T-C-C-G-A-T, knowing that T pairs with A and C pairs with G and C pairs with G and G pairs with C and A pairs with T and T pairs with A, the unwanted DNA, say from the virus that's infecting you, will bind to this. It will break the beacon open and it will cause the floor to be a long way away from the quencher, and now the thing will glow. If you have green DNA there, well, okay.

So the thing wrong with this is, of course, if you've got a lot of DNA and and your body, and the stem is holding the beacon together, is made out of G-C, T-N-A, there's bound to be some DNA somewhere floating around your blood that's complementary to the stem region. And so the DNA will be invading that stem and separating the floor on the quencher, causing the floor to glow. And that means that you will get what we call in the business a false positive, which, if you could imagine, the only thing more annoying than being told that you have an HIV infection is to be told you have an HIV infection when you do not, right? And so this gives you background and false positives. And so by putting funny bases, and we are referring to these as a component of an artificially expanded genetic information system, Aegis, that's what the acronym comes from. Of course, the minute you have the stem held together by Z-P pairs or S-B pairs or whatever, you don't have to worry about that beacon being intubated. And in fact, that's that's that's that's a remarkably useful tool.

But this is actually a branched DNA structure that is actually used to measure viral load in patients' bodies. People who have HIV, hepatitis B, hepatitis C will actually use this assay where people are trying to detect, I say, 8 molecules of the virus per milliliter in blood. And we actually put the non-standard artificial nucleobases here and here to improve the signaling of the nanostructure, suppressing noise, just by making this assembly, which has many signaling units per one capture of one target DNA, not be invaded by the natural DNA. This is a hundred-million-dollar, your product. I don't want to encourage any of you to get HIV or hepatitis, but if you do, you might have the pleasure of knowing of a small fraction of what your healthcare provider pays for your personalized care. It comes back to the Westheimer Institute in the Foundation for Applied Microevolution to support our research. So we're actually quite happy about this. But again, isn't so that's how the artificially expanded genetic information system pairs. We gave crystal structures of Farnsworth. Ugly. It does all the static things that you expect from nucleic acids.

But remember, life is a self-sustaining chemical system capable of Darwinian evolution. So one of the questions is whether a six, eight, ten, or twelve-letter DNA, remember, you just have a four-letter DNA, so you're inferior. Six, eight, ten, or twelve-letter DNA can it evolve? And particularly, can it adapt? And while we're at it, we might as well get it to evolve and adapt to do something useful, like binding to cancer cells. And so here is a relatively simple scheme. It was developed initially by people like Jack Szostak and Jerry Joyce and Larry Gold and Andy Ellington, where you start by taking a library of many nucleotides containing G, A, C, T, Z, and P. We're just going to do the six-letter version tonight. The eight-letter version, that's too complicated for the evening. And you know, that's a random variation. Well, we'll bring along some target cells, say cancer cells, and we'll mix the library with the cancer cells. Now, of course, most of the library members have no function. So most of them do not bind to the cancer cells. But a few of them do. And so you can wash away the ones that don't. And when you do, you recover a few that do. You separate them. These are the so-called survivors. Now, these are DNA molecules built from a six-letter genetic alphabet: G, A, C, T, Z, P. The Z has a nitro group on it for the chemists. There's extra functionality. We've got more stuff on the extra letters. So that means they have more functionality. They are more likely to have some in that library that bind. And now the evolution has fun, right? We made G, A, C, T, Z, P, six nucleotides. We then had let them have children. Remember, DNA can be copied. The copies can be copied. The copies of the copies can be copied. And the copies of the copies of the car... I'll stop there. You can make a lot of the copies of the survivors with mutations, sometimes where the mutations are themselves replicatable. And now what you do is you get a new library. But this new library is no longer a random library. It's one that has evolved under the selection pressure that we must bind to the cancer cell, or else we'll get washed away. There's an in vitro laboratory evolution experiment. So the new library is the descendants, the kids, the children, if you will, of the survivors who survived the selected challenge, not avoided being gored by the Mastodon, but rather the ones that have been able to stick to the cancer.

So, okay, so now what you can do is repeat the cycle. This time, of course, with a library that is enriched in molecules that bind to cancer cells. And of course, in the next cycle, what you will happen will is they fit children, the ones more likely to survive the selection, the ones that are more likely to bind to cancer cells will survive even better. If you do a number of these cycles, round and round, around, I won't even go there. After a while, you'd begin to see all of a sudden, up comes some cells, some molecules with a six-letter DNA that bind to cancer cells. This is after 11 rounds of selection. But this is quite fast with just standard cells, standard DNA, four letters, not a lot of stuff, right? Sorry, no, not a nitro group, but not a lot of stuff. That we have one Z and P. It takes you to 18 or 20 rounds of selection to even begin to see this kind of. So the six-letter DNA is evolving faster than four-letter DNA. And eventually, you can go back and get some of these. We can determine their sequence. There you go. There's the sequence of a DNA molecule which contains Z and P, which I put in red, which binds to cancer cells. This is a useful diagnostic. More important, we make it. This cell, by this. This. I explained that what this plot is. This is the intensity of a cell, and this is the number of cells having intensity. What do I mean by intensity? Well, we put a little fluorescent marker on a molecule that has evolved out of the selection pressure. And so if the cell binds a lot of them, the cell has a very strong green glow. Um, actually, if we now start removing the Z's and removing the P's, that is, removing the funny bases, going back to just the four letters, tend to lose the binding to cancer cells. That is, they remove the Z and P, the binding goes away. Then Z and P is important for the binding. By the way, we can do more within this. I mean, we can actually take extra letters in the nucleotide alphabet and write extra proteins in amino acids into the protein lexicon. This is actually work that was done by Chris Switzer and Jim Bain, now close to a good grief, I'm getting old, twenty years ago. Their horizon is really unlimited with these extra cells. And remember, reproduction isn't alone, not sufficient to support their winning and evolution. It's got to be reproduction with mistakes, reproduction with errors, where the errors themselves are reproducible. That's the key element here. So yes, in general, A pairs with T, G pairs with C, Z pairs with P. Your biochemistry course is going to be a lot more complicated, but never mind. S pairs with P, A with V, J with K, X, most of the time. But sometimes mistakes are made in this copying. Those are the mutations from which you can actually do evolution or selection within this system. And that's, of course, what makes this Darwinian.

Well, for those of you who are science fiction fans, if you listen very carefully to E.T., you'll discover as E.T. is dying for the eighth or ninth time, and that element being brought back to life, the kids crying each time, you can hear saying that E.T. has a six-letter in the alphabet. So this is actually has precedence in the science fiction literature, not as old as Mary Shelley. Um, I should say that they then listen to the chatter, they say one is diamine of purine and that diamine, you know, purine, and the other is a pyrimidine which we cannot identify, which means that these videos were not very good scientists. This picture, by the way, I cost me $500. I had to pay Steven Spielberg to let me put it in the book.

So then what about risk? Okay, what about risk? Okay, so you say, hey, we've got a six-letter genetic system that is not quite self-sustaining in terms of evolution, but it's capable of evolving. And I'd love to put this risk diagram up because this is actually Eric Schmidt, who is the biosafety coordinator of the European Union, who made this following point: that if you're dealing with an organism which has an alien genetics or an alien core molecular biology, it actually is not quite necessarily toxic. And he draws this Venn diagram. Okay, within the red circle are all organisms that you might construct that have the standard Terran biochemistry. Outside the red circle, you do not have standard Terran biochemistry. So these are interesting parasites. Remember, you and your, I mean, the most nutritious food is the food that's most like you, right? That's just because you are looking for nutrients and and so you have to get the nutrients from. So meat is more nutritious to you, by this lighter than grass, for example. But the argument now is that if you are using standard chemistry, right, the organism that uses it is a parasite because he finds you tasty, right? So, um, we are, of course, in our system, entirely outside of that. We're making something unnatural, which is why Eric Schmidt says xenobiotic, and why it's a quote, ultimate biosafety tool. You know, within the green system, of course, it's capable of evolving. Outside the green system is not capable of evolving. Of course, the thing is not capable of evolving, it really is hardly at risk at all, right? Because, you know, they can't evolve in response to challenge, we'll eventually die. Um, inside the circular here is self-sustaining. Outside the surface, it's not. Circle. The blue circle now is not self-sustaining. That means it needs to be fed. Um, what we're trying to do is, of course, going back through the system where we're trying to use unnatural stuff. We're trying to make it capable of evolving. Of course, we're a long way from getting it to be self-sustaining. Um, Craig Venter, however, as you may know, with Ham Smith, produces cell, which uses standard Terran biochemistry, is self-sustaining, it's capable of evolving. So it's right squarely in the middle of the risk circle. You just have to remember what Craig synthesized was really not materially different from what is already out there in natural biology. So it may be risky, but it's not, not a new risk. So there you go.

So I told you now about observation, and of course, exploration is part of that. We've talked about it. Analysis, I have not talked about origins. We've talked about synthetic biology. What we can say is that yes, we can construct, okay, using a scientific method that is more complicated than what we were taught in school, where our biases are jarred by exploration, for sure, no question about that. Um, natural history certainly is expanding our view of what life could be like. Is RNA life only before proteins emerge? That's a possibility. And science, of course, is this human intellectual activity which has a process that is an appropriate way able to dislodge the scientist from always coming to the conclusion they set out to conclude. And synthesis, in this respect, is the ultimate tool. It, it drags this scientist across territory, uncharted territory, where they're forced to solve unscripted problems. And if the series inadequate, it crashes. And therefore, synthesis can drive discovery and paradigm change as well, better than analysis and observation by themselves. So what is life? Well, still don't know. But we seem to be able to get something that we have value in life, adaptation to perform a function, you're binding to cancer cells as the example that I showed you from a functionalized nucleic acid with extra letters in the nucleic acid alphabet, designed by synthesis, made by chemists, able to replicate with imperfections, of course, where the imperfections are themselves replicable, and therefore able to evolve. No, you know, we talked about lighting as a sustaining chemical system capable of Darwinian evolution. You say, but this is not self-sustaining, right? But of course, that's what we emphasize, system in this case. And of course, the difference is between this and that twelve-letter Darwinian in a system capable of assisted DNA. This is a Darwinian evolution of tests. It was more than obvious. So with that, let me stop. I'll thank you for your attention, and I'll be happy to answer any questions you might have. Well, thank you. Thank you, Steve, for that very thought-provoking lecture. We have time for questions. Would you like to moderate your own? From IP is the one thing that you should do though is to repeat the question. My last, in case people can't hear. All right, say be running around with the microphone. We've got a hand right there. Yes. Say loudly, and I will repeat the question. Yes. Where's your periodic table in this room? They don't have one. Absolutely. Well, John Baris and I wrote a book under the auspices of National Academy of Science. Oh, yeah. So the question is being asked is whether or not I'm making the assumption that carbon-based life is what we're doing here. I mean, you saw a lot of carbons there, and you saw no silicons, right? Well, that's right. So the, the, the definition of life is a self-sustaining chemical system capable of Darwinian evolution. Is a theory of life, but it makes the assumption the only way that matter can be organized in a way that gives us properties that we value in life is through Darwinian evolution, this process. But it does not make the assumption that you don't have silicon, right? If you cannot mean tellurium instead of sulfur, there's all sorts of analysis that you could analogies that you can make. I mean, arsenic instead of phosphorus is one that was we were worried about a lot. So there's no question if you can construct a working system which gives you Darwinian evolution out of silicon, that will pass the muster for life by this model. It's a theory of life. It's a statement. It's deeper than a definition. It's basically a statement saying that this is the only way we think it's possible to get, you know. Now, keep in mind that if you ever, I knew presumably as a human species, are not far from this point, if you ever get to the point where you're able to do germline manipulation so that you anticipate future things and change the DNA in the germ lines that are producing your babies, this is something that is not allowed by Darwinian evolution. You're not allowed to have prospective mutation. This would be called maybe Lamarckian evolution. Of course, the question is, when the human civilization adopts it or creates that technology, will it cease to be alive? Right? That's sort of the paradox of this. But, but yes, but yes, no, we've tried. I mean, there was a John Baris and I, we put together a report with the National Academy on weird life, as it was called, and it was published at about 2010. You can get a copy from the National Academy, where we tried to come up with systems based on silicon, based on avoiding as much carbon as possible. And one can conceive of these. They have never actually been synthesized. But you're a synthetic chemist. Okay, so it's going in the wrong direction. Yeah. Another question. No other question. Oh, in the back. Oh, well, yes. Yeah, I mean, absolutely. If you go out and find data, so the question is whether a robotic system, right, if you go out and find data in the cosmos, would you say that data is life? And that's, of course, the subject of many Star Trek Next Generation lots. And the answer is, we would probably say he's a biosignature. And as he was, the evidence is something that was life made him. If that's only because we can't conceive in our feeble, we're looking at it, of him coming out of a spontaneous generation from a suit. But that's just that's just us. But yes, anything that's capable of Darwinian evolution, even if it's a robotic structure, would be called life by this. In the back. Yes. Cope in unscripted hypothesis. Sure. Well, I mean, I mean, keep in mind that what we do is science. When we're doing routine science, we kept control over the hypothesis that we choose. And of course, anybody, especially if you're trying to write a grant application, does not pick a hypothesis that is difficult to test. So you would tend to have scripted hypotheses. And the science fairs are well known for these, right? You use are my cat left-handed or right-handed? This is a common thing. But what a synthesis, right? You know, you, you're being driven by the goal. And so you don't have the option to pick and choose your hypothesis. The hypotheses that you must deal with, the theory Kellman's, you must deal with, are the ones that you're relying on to get that synthesis to work. And so that's what we mean by unscripted in that context. Yes. Yes. I absolutely know. If you would like to do that. And there's a no. We, the problem fundamentally is that with carbon, nitrogen, oxygen, and hydrogen as the only elements from which you can build it, it is actually very hard to build a small thing with three prongs or three holes without having a charge on that particular molecule. The big thing is actually you can do. So the reason why you only see 12 bases and six base pairs is set of 16 bases in eight base pairs, 2, 4, 8, 16, which is what you would expect. It has to do with the constraints of chemistry associated with how many bonds carbons, oxygens, nitrogen's, and hydrogens make. So it's very core to the chemistry. So you cannot get this from the prongs story. You have to go back and look at those structures. That's that's a very good question. However, very observing. I have to worry about this person. Yes. It's let me summarize that for those in the back. Absolutely. So the question is, right, Miller and Urey made up a model for what they thought the early Earth atmosphere was like. And so they put a lot of energy through it and got a lot of goo out there. And then eventually they could get out of that goo amino acids. And that's a very important initiation of pretty much modern prebiotic chemistry. So the question is, what we go to other planets as well, and we might be able to make models about what their environments were, do the same kind of experimenting, getting different, I mean, we can go to a planet which is dominated by silicon hydride in the atmosphere and try to get silicon, silicon life out of this. What should people? And your problem is, yes, I mean, I would love to do it. Keep in mind that almost all of the problem has to do with the uncertainty of the ancestral atmosphere and the ancestral environment. So ASU has, of course, a wonderful astrobiology organization, which is very much involved in this. And, you know, they will tell you, I mean, I don't know jack. I mean, some days it's Mondays, Wednesdays, and Fridays is that well, if the oxidation state is more, and that's it, you know, it depends on the model. So that's a large amount of uncertainty, meaning relatively little constraints on what you can actually get. Now, Titan, for example, is a moon of Saturn. It's got a lot of organic stuff going around it. And, you know, I mean, we've, it's a rich source of organic molecules. And I love that you forget a life form that could live in methane liquid at 95 Kelvin. That's about minus 200. Yeah, exactly. So your Earth, unfortunately, has been poisoned by these plants. They put all this oxygen in the atmosphere, and then it really destroys the ability to do good organic chemistry. That's anything that you put out onto the table gets toasted, right? The butter goes rancid, the toast, the bread becomes toast eventually. And so you have a problem with this. And and then, of course, you know, we don't, we have a big fight going right now. So what minerals were available in early Earth? I mean, I love to have borate minerals, I love to have gypsum, I would love to have molybdate minerals. We'd love to have these in a dry desert environment, not actually unlike Death Valley, and honestly, I'm like Phoenix. But then I got geologists assigned to me that their models for early Earth have so much water on them that there was no dry land. And so I can't have a Phoenix, everything submerged as a Kevin Costner Waterworld. And so, and so you'll find that when you try to model what the early Earth looked like, and then what early Venus looked like, or what early Mars looked like, you'll get consensus on the direction. Almost everybody will be that Mars had more water than than it has now. Venus was more habitable then than it is now. But you won't get a lot more constraints than that until we do a lot more work. Yes. Yes. Yes. We're trying to get them both in the same. We're trying to get the functional stuff and the information the same mall. And maybe I missed it presenting it. Yes. So the question is, knowing why do we, how do, why do we take this chicken and egg problem seriously? So right now, you have, of course, a three biopolymer system. You have DNA that passes information from you to your kids. You've got proteins which does most of the stuff that needs to be done. And you have RNA which carries information from the protein stops, right, from the DNA molecule to the ribosome to make the proteins. And your problem now is the creationist irreducible complexity problem, right? No one, no one knows how DNA arose from prebiotic soup. No one knows how RNA arose from pre-bases. We even have any problems getting proteins out of pre-but actually, where those these tend to be a little bit easier. How you would get all three of them at the same time, where one is performing the genetic role, one is performing the functional role, and one is the messenger between the two, is just a problem that is a complexity irreducible origins problem. So everybody was very, very happy when Tom Cech and Sid Altman back in the 1980s discovered that RNA, in addition to being a genetic mom, and there are RNA viruses, for example, could also do catalysis. As we said, hey, that problem is solved, right? We don't have to get proteins and DNA and RNA and ribosomes and machinery to all rise immediately to get life going. All we need is an RNA molecule that will itself be a catalyst that specifically catalyze the tip with directed synthesis of another RNA molecule, its son or daughter. And then life, we get started. Is that RNA enzyme that catalyzes the synthesis of RNA from an RNA template would be imperfect, but the imperfections would be replicable, okay? And so that's where this story goes. That's why we look for a single biopolymer. So it could be proteins. People have argued that proteins were the primordial biopolymer, RNA came later. The only problem is that proteins don't have any easy Watson-Crick big, small prongs hole replication potential. And so, you know, that's why RNA is better. At least with RNA, I can imagine replication principles. So that's where that clear is that. So we are up against a chicken or egg problem. We have to this very complex system, which is your modern metabolism. We had to simplify it. We had to simplify in a way to get one molecule to do both catalysis and genetics and do stuff as well as encode stuff. And we get one molecule. Then we had to where help out that one molecule arose. That's so hard enough problem without having two or three. Yes. Yes. So we're using the property of a 12-letter, or in this case, six-letter genetic system, putting it under evolutionary pressure where for part of it, it's folding to bind to cancer cells, it's doing stuff like a protein, and then another part of that cycle, it is being copied like a genetic. Yes, sir. Shoot. Yeah, I guess so. Yes. Yeah, I mean, keep in mind that there's a two questions you're asking. The questions whether they're more error-prone intrinsically, or whether they're more error-prone in our hands. Yeah. So intrinsically, actually, they are probably less error-prone because the A-T pair joined by only two hydrogen bonds is weak, and all the funny ones that we have are joined by three hydrogen bonds. So this is a very, very, very error-free system when it's just coming to hybridization. The problem is that when we make copies of it, we actually use enzymes which we get from natural biology. These are enzymes that have evolved for billions and billions of years to take G, A, C, T, and not Z, P, S, P, or any of these other things. And so those enzymes, we mutate them, we evolve them, we do engineering on them, we do all sorts of stuff to try to get them to handle our funny alphabet. And so those are more likely to make mistakes with our funny stuff because they're unnatural, not because they're intrinsically bad. Yes. Paul, so you raised the question about whether making new forms of life is risky, and you've persuaded us that the risks are very low. And then the flip side is, is it useful? And you've given us some examples of what's been done. But this is presumably the tip of a huge iceberg, and the future of synthetic biology must open up all sorts of wonderful possibilities, possibly further risks. Can you just say a few sentences, say, you know, what's next on the agenda? For sure. I mean, I was embarrassing because there's a good chemist, organic chemist, synthesis is what we do. It's not a field. So when I woke in 2004, there was an article in Nature and in Scientific American telling me that Pete Schultz and I had both invented synthetic biology. And together, I called Pete, said, did you invent synthetic biology without telling me? And he said, no, but we're gonna write it into the next grant application. So, but synthesis, of course, is an old field in chemistry. Almost all the compounds that you have in your clothing as dyes are synthetic. And of course, biology became synthetic in the 1970s with the recombinant DNA technology. And there was a big concern at the time as to whether or not this would lead to plants that would escape the laboratory, bugs that would have saved a Leger Praetorian be harmful. There was a huge conference in Asilomar in California where rules were set out. Over the last 40 years, we've come to pretty much understand that there's not a lot of risk associated with this. But there are still some people who don't like genetically modified organisms. So right now, they'll make plants, right, which will be resistant to herbicides. You plant the plant with herbicides, you put herbicide down, all the weeds die, and the plants grow better, and they're cheaper. So, and I mean, a good biochemist will tell you, and I will be one of them, that this is not materially different at all from the plant that you get. But the futures are hard to say. I mean, the future, basically, we are desperately trying now to get E. coli to metabolize steps here that will enable us to get Z and P, for example, made inside of an E. coli. So, tribe, right? That's gonna ask you, can you upload this stuff into cells? And take it away? Your guests in the chemistry department actually has contributed one of the enzymes. So one of the steps in that metabolism. So we have that metabolism working in E. coli. I have not, did not talk about it because it's a little premature to speak up. But yes, again, E. coli is able to maintain plasmids that contain funny bases. And of course, the funny bases now will be used in diagnostic systems. And so you will have an E. coli package there's able to do a complete diagnostic workup of you right now. So don't have to pay money for each. And that's certainly isn't it. So unlike dogs, which are human creations after all, but very close to wolves, we're dealing here with truly novel organisms that could, in the very near future, be autonomous. And that's that's a big problem. We, the autonomy of these things, especially it's also true with just recombinant DNA organisms, it's less than we would like. They're dying. No, when we try to keep them alive. But in principle, yes, you could have all time. Right? So the problem that would be that this poor guy, he dropped now in the world, he wants to go find some Z to eat. That's right. Yes. No chance. Yes. Not so we've created a whole ecosystem. Yes. Like the next step. All right. Well, I think we're going to have to draw it to a conclusion, not least because you need to sign books outside. So before we wrap it, these occasions take a lot of organization. And my staff, particularly Adriana Fontes, who ought to be around somewhere, and Katie and Alisa at the back there, you all have met them on your way in, and several others who have helped out over the weeks in in promoting and dealing with the website and encouraging you all to come. And so I think a round of applause for them as well as for our speaker. And see you all next time. Drive safely.