Princeton Powwow: RNA World's Last Hurrah?
Wednesday, 16 January 2013, 3:05 pm
Article: Suzan Mazur
PRINCETON POWWOW: RNA WORLD'S LAST HURRAH?
By Suzan Mazur
SARA IMARI WALKER
"I think we need to move away from treating a strict RNA world scenario as the central accepted answer for the origin of life because most of the origin of life community don't think that's the definitive answer." -- Sara Imari Walker
Is next week's Origins of Life conference at Princeton University the RNA world's last hurrah? The Origin of Life community has largely rejected the RNA world, biochemist Pier Luigi Luisi recently describing it to me as a baseless fantasy. I asked physicist Sara Walker to weigh in. Walker is on the adjunct faculty at Arizona State University, a NASA postdoc fellow who is one of the presenters at the upcoming Princeton conference.
Long embraced by NASA despite decades of failed experiments, the RNA world is the organizing point for the Princeton gathering, which is co-sponsored by NASA. Walker acknowledges that the Origin of Life community does not think the RNA world is "the definitive answer." And NASA's award of $8 million in September of last year to Carl Woese et al. is proof that origin of life remains a largely philosophical discussion, with Woese telling me in October (sadly he died in December) that we don't know what life is, and that his grant to study the principles of the origin and evolution of life signalled that NASA is rethinking its approach to the origin of life problem.
Walker, who is a collaborator of ASU's Beyond Center director, Paul Davies, says she also finds inspiration in the work of Carl Woese and Nigel Goldenfeld regarding collective evolution and horizontal gene transfer along with the ideas of Stuart Kauffman and others on self-organization as an evolutionary process.
Walker thinks "biological systems are dictated by the flow of information . . . how information is handled and processed can distinguish living from nonliving."
One of the interesting points of the Princeton conference is the attempt to open it up to parties beyond presenting scientists. A good thing. What's the big secret anyway? That the RNA world is a bust? That public money has been wasted?
The conference should be wide open to the public, held in a theater like the World Science Festival is, and streamed over the Internet. Public funding might then be a lot easier to come by for Origin of Life researchers.
Here's an internal email from the principal organizer of the Princeton conference, Laura Landweber, which I was able to access, discussing the possibilities of informing a wider audience.
"From: Laura Landweber lfl@princeton.edu
Date: December 29, 2012 9:35:25 AM EST
To: Recipient List Suppressed
Subject: remember to register for Origin of Life conference
If you plan on attending many of the origin of life talks the week of Jan. 21-24, then please register (which is free), because the room capacity is almost full, and then the meeting will be closed to registration (but we are working on webcasts, and there's also a video monitor outside the lecture room)".
Excerpts of my interview with Sara Walker follow.
Sara Walker has a BS in Physics from Florida Institute of Technology and a PhD in Physics and Astronomy from Dartmouth College. Prior to ASU, she was a postdoctoral fellow at NSF/NASA Center for Chemical Evolution at the Georgia Institute of Technology.
Some of Sara Walker's professional activities (present and past) include: Administrator, S.A.G.A.N. (Social Action for Grassroots Astrobiology Network); (and at Dartmouth College) Co-founder, Graduate Women in Science & Engineering; Co-organizer, Women in Science Mentoring Program; Community Service Award.
Suzan Mazur: It's good to see that about a third of the presenters are women at the Princeton Origins of Life conference next week, where you are a featured speaker as well.
Sara Walker: Yes.
Suzan Mazur: You were co-organizer of the Women Science Mentoring Program at Dartmouth a couple of years ago, which paired graduate women scientists with high school girls. Would you talk a little about the success of that mentoring program?
Sara Walker: It was indeed very successful. We took a group mentoring approach. A few graduate women in science met weekly with high school girls who had demonstrated a strong interest in science. It was so much fun. These girls lit up when we talked about dissecting frogs and things like that. It was not the kind of conversation they were used to having.
They also didn't really know what the college experience was like. We had an opportunity to walk them through it and introduce them to new ideas. It inspired me to see them inspired, so excited, wanting to know how to get into science while still in high school. Because when I was their age I wasn't sure what the world of science was all about.
Suzan Mazur: You're now collaborating with the esteemed Paul Davies, director of the Beyond Center at Arizona State University. Can you tell me when you first became interested in science?
Sara Walker: My interest in science began in high school but I didn't know what specifically I wanted to do in science. It was at Cape Cod Community College in Massachusetts, which I attended for two years, where I decided that I wanted to actually be a scientist. I took a physics class first term with Professor Shaw. I can still remember walking in to Prof. Shaw's class the first day and Prof. Shaw telling us about magnetic monopoles, these very illusive objects that had been predicted by theory but had never been identified in the laboratory. It was mindboggling to me. I was so excited about being enabled to then go out and look for these things.
After CCCC, I really wanted to be a physicist. I thought scientists who did theoretical physics, particle physics and cosmology were the absolute coolest people on the planet. I continued my undergraduate work at Florida Institute of Technology and then went to Dartmouth where I worked with Marcelo Gleiser.
Suzan Mazur: Marcelo Gleiser was your PhD advisor at Dartmouth, the Brazilian scientist, who is one of the participants at the upcoming Origin of Life meeting at CERN.
Sara Walker: Marcelo really got me interested in astrobiology and the origin of life. He told me that cosmology was cool but that he'd just started a project on origin of life and would I be interested in participating. I said sure.
Suzan Mazur: You've written a paper recently with Paul Davies called "The Algorithmic Origins of Life." Would you establish what you mean by an algorithm?
Sara Walker: An algorithm, in the context of the paper, is a program that allows the active use of information -- information processing -- which is really important to biological systems. It's not just that biological systems store their information in molecules like DNA, but that they actively use this information to operate.
Suzan Mazur: So the algorithm is a program that allows the active use of information. What about the information itself?
Sara Walker: Information can be loosely defined as events that affect and direct the state of a dynamic system. Saying that information is algorithmic really means that specific events are programmed to have specific outcomes in biological systems. So it's really the processing of the information that's unique about how biology operates.
Suzan Mazur: You say that at some point "information gains direct, and context-dependent causal efficacy over the matter it is instantiated in". What is the information you refer to?
Sara Walker: In this case it is the state of the system, an example the connections or topology of a biochemical network, so it is highly distributed. Function arises due to the distribution of information, therefore biologically meaningful information only arises in the context of the wider system.
Suzan Mazur: In your paper you discuss progress being made in understanding where and when origin of life happened. Other scientists I've interviewed differ. Gunter von Kiedrowski, for example, has told me the following: "We can't travel back in time, we'll never know the historical course [of the origin of life]." Steen Rasmussen told me essentially the same.
And Doron Lancet said this: "We will likely never know what were actually the exact chemical substances that began life. But we can wisely guess what principles such chemicals had to obey."
Would you comment?
Sara Walker: I do agree with those statements. The point is we've made a lot of progress looking at isolated parts of the problem. Identifying what some of the conditions on early Earth were and what you can synthesize under those conditions, what in biology seems to be essential molecules. But to move beyond that and prove an origins story, that's where you really need to get the deeper principles. The examples you gave from von Kiedrowski, Rasmussen and Lancet point to the fact that while we may never know the precise details of the chemistry or the exact sequence of events, we may still figure out the deeper principles at work.
Suzan Mazur: Doron Lancet also told me that we can't even say there were lipids way back when, that what existed might have been lipid-like. And he said it's also very assuming for us to be thinking that the way life is now with 20 amino acids and four nucleotides is "how life should have been from its inception" -- it could have been any set of molecules jump-starting life.
Sara Walker: I totally agree with that.
Suzan Mazur: So have we made progress on when and where it happened if we don't know what the chemicals were and it doesn't matter what the exact circumstances were? Lancet said further: " [I]f people tell you life began at a temperature of 25 degrees Centigrade, 110 degrees or 360 degrees (in suboceanic vents) -- this doesn't matter. What does matter, is the principle of what would constitute acceptable molecular roots of life, and at the same time have sufficient simplicity to warrant emergence from an abiotic mixture of chemicals."
Sara Walker: We don't even know which chemical systems came first. There's a huge debate between lipids or genetic polymers or peptides. We just don't know, and I agree the best way to find answers is to look at more general principles than precise chemical details.
Suzan Mazur: So all three questions are still up in the air -- when, where and how.
Sara Walker: Yes. We definitely are still up in the air in the origins of life investigation. But one of the reasons I'm optimistic about making headway in uncovering the deeper conceptual principles about origins of life -- the how -- is that scientists are understanding biology better. We're looking at things at a mechanistic level, observing biological systems operate, i.e., how protein networks function, etc. The problem is that we have to extrapolate from the chemistry and specific details of the life we know to try to figure out the more universal ideas that might be characteristic of any living system including those we haven't identified yet. That's really the hard part.
Suzan Mazur: Do you agree with the late Carl Woese that our Last Universal Common Ancestor was a process not something material?
Sara Walker: Yes. I'm a very big fan of Carl Woese's work. He's had a lot of brilliant insights into early evolution.
Suzan Mazur: It's very sad that he's gone, he had so much more to say.
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NOTA CAUSTICANTE DESTE BLOGGER:
Alô MEC/SEMTEC/PNLEM: o cenário (nem teoria é) do 'Mundo RNA' é, segundo Pier Luigi Luisi é uma fantasia sem nenhuma fundamentação. Nossos alunos do ensino médio precisam saber disso nos livros didáticos de Biologia do ensino médio na abordagem da origem e evolução química.
Os mandarins da Nomenklatura científica vão espernear com esta conferência de 'magos' da Origem da Vida, porque seus vaticínios serão outros, menos os que a camisa de força da agenda do materialismo filosófico tem imposto aos cientistas.
Mundo RNA quem diria - fantasia sem nenhuma fundamentação!
Pano rápido! que em ciência a verdade de hoje é mentira amanhã!!!
