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NASA Reproduces a Building Block of Life In the Lab
xp65 writes "NASA scientists studying the origin of life have reproduced uracil, a key component of our hereditary material, in the laboratory. They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces this essential ingredient of life. 'We have demonstrated for the first time that we can make uracil, a component of RNA, non-biologically in a laboratory under conditions found in space,' said Michel Nuevo, research scientist at NASA's Ames Research Center, Moffett Field, Calif. 'We are showing that these laboratory processes, which simulate occurrences in outer space, can make a fundamental building block used by living organisms on Earth.'"
I have a feeling that this will lead to the speculation that Earth was therefore seeded with fundamental biomolecules from space and this paved the way for life to begin on Earth. I hope people don't jump to this conclusion too quickly. Personally, I find it unlikely and think there is a more likely interpretation, which I will get to in a moment. The reason this is unlikely is that just having biomolecules is not enough to start life processes. Especially in the time frame when life is hypothesized to have originated (~3.8Gya), as the surface of the Earth was completely covered by ocean at that time, and any seeding of organic molecules from external sources runs into the concentration problem: the problem of getting enough of the right molecules in the right place with the right concentration and the right inputs of energy and raw materials for biochemistry to begin. Any such seeding from external sources would end up very dilute, and biomolecules would likely break down before they could be gathered in sufficient concentrations.
Personally, one possible interpretation which I prefer is that these findings (and similar ones of finding amino acids in comets and such) indicate that organic biomolecules are fairly common and will form anywhere you have C, O, H, N, S, etc and energy. Not only would this indicate that biomolecules could form fairly easily on Earth, but that they are common in the universe, and organic life may arise just about anywhere you have an input of energy and raw materials and a way of concentrating those molecules so they will react and form self-organizing and self-replicating biochemistry.
My current favorite hypothesis about the origins of life on Earth are those championed by Martin and Russell. They hypothesize that life on Earth began and alkaline hydrothermal vents in the ocean, around which porous rocks of iron and nickel sulfide would form semi-permeable cell-like compartments in which basic organic molecules formed by the geochemistry of the vent could concentrate and react with each other. Raw materials would be constantly input from the vent, and there would be a constant energy gradient in the form of heat, pH, and proton-motive force. This neatly solves several problems of many hypotheses of abiogenesis: the energy problems, the raw materials problem, and the concentration problem to name a few. They outline the overall picture of going from geochemistry to biochemistry to prokaryotes to eukaryotes in this 2003 paper:
On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells - Martin and Russell, Phil. Trans. R. Soc. Lond. B 29 January 2003 vol. 358 no. 1429 59-85
They further clarify the possible pathways for a shift from geochemistry to biochemistry in this 2006 paper:
On the origin of biochemistry at an alkaline hydrothermal vent - Martin and Russell, Phil. Trans. R. Soc. B 29 October 2007 vol. 362 no. 1486 1887-1926
A search for either of those followed by clicking on the "Cited By" link on Google Scholar will yield many papers, including some actual experiments supporting them, which expand and clarify these hypotheses. Definitely worth a read if you are interested in the possible origins of life on Earth, as well as perhaps some ideas of what to look for when looking for life elsewhere.
Anyway, point being, this is fantastic work by NASA, and an excellent example of showing that these molecules can form naturally. Just be careful about drawing any definite conclusions from them other than the simple conclusion that Uracil can form in these natural conditions, and possibly or probably others.
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
This does not show that the basic building blocks of life were made by entirely natural processes. This shows that a component of one of the building blocks of life can be made by natural processes. I don't think we can use induction, in this case, to try to say that since we uracil can be formed with natural processes, all building blocks of life can be, too. Not to mention the difficulty in getting "building blocks" or "components" to end up forming the actual thing that they are components/building-blocks of.
I'm glad they at least included this part, eventually:
Nobody really understands how life got started on Earth.
I wouldn't be so sure that ten years from now this kind of research will be allowed, at least in public institutions. Don't forget that until recently there were bans on publicly-funded research which used cells from deceased embryos and lab-created blastocytes, because they "have souls".
That's just stupid. Simply put, there has to be a lot more fundamentalist Christians than there are for such a thing to come about. My view is that the embryo ban came about because it was an icky, new technology like cloning or artificial insemination. After it's been around for a couple of decades, nobody but a few people will give it a second thought.
This shows that a component of one of the building blocks of life can be made by natural processes.
The Miller-Urey experiment was also fruitful here. Over modest timescales in likely primordial Earth environments it appears that the building blocks formed are the ones commonest to all forms of life-as-we-know-it. The leap from "could have" to "did" is getting more manageable every few years.
The experiment in TFA goes further - finding methods for synthesis of the components not on a primordial Earth, but in space. This is a net positive for the panspermia theory. Oh, and BTW: you left off an important part of that quote.
Our experiments demonstrate that once the Earth formed, many of the building blocks of life were likely present from the beginning. Since we are simulating universal astrophysical conditions, the same is likely wherever planets are formed," explained Sandford.
We'll know more when we start dissecting comets, and even more when we dissect comets that orbit other stars. The tricky thing about life is that it takes darned little of it to make all of the life that we see.
Help stamp out iliturcy.
I agree that research should be allowed on this stuff but some of the opposition isn't crazy Christians. People like me are concerned about at what specific point does a person turn from a pile of cells to a "human". This has nothing to do with souls and more to do with defining important things like what constitutes murder. When is the magic point where some living thing goes from being thrown away as abortion waste to being something so valuable that society could potentially put someone to death for killing it.
I know that wasn't the exact point you were trying to make but I just wanted to voice that not everyone is opposed to something because of religious reasons. Some people have moral questions, separate from religious beliefs, that question how we treat living things.
I think this scientific research is way more important than a national health care plan, yet I still think boundaries should be respected if a valid reason is brought up. I know we now know how to obtain special cells easily without harm to anything, but in the past that wasn't exactly the case and I think that set off the panic that got the research criticized so much.
Mods can have my karma if they want it, its still a purely religious assertion to say that life spontaneously arises.
There's no definitive reason why it couldn't have happened, we observe life on this planet, and there is no real competing hypothesis, so it seems a reasonable, though speculative, hypothesis to entertain. Not certainty like the "God did it" crowd seem to have, but a rational inference from the data :-)
It's unobserved and there's good reason to believe its impossible (e.g. the chirality problem).
I wasn't aware the chirality problem was evidence towards abiogenesis being impossible, more that it presents a very interesting and challenging question as to why one particular handedness become dominant.