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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
There's a committed portion of the US population who don't need to "head..towards understanding the origins of life" because they are absolutely certain that they know exactly how life came about because some Bronze Age scroll tells them so. They're not going to take kindly to anything that could challenge their certainty.
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".
You think so, and I think so, but a very vocal and (seemingly) influential minority thinks it's heresy.
You are welcome on my lawn.
Uh, no. They pretty much deny a number of facts. What they deny will change over time, and often will change depending on the audience. I have had Creationists deny in one moment any evolution beyond species variation, then the next claim that some degree of macroevolution is possible, then in the next try to rearend Biblical "kinds" into genuses and families. In fact, the only thing that Creationists can be counted on to declare as "fact" is that no matter how much evolution is going on, men and apes are not related.
The world's burning. Moped Jesus spotted on I50. Details at 11.
On a cosmological timescale, if the separate parts are capable of coming together, then their existence makes that event an inevitability.
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.
We can't use induction as proof, because this is not mathematics.
We can use induction to say that we can reasonably expect to discover that other building blocks can form from natural processes as well, though. At the very least, this reduces -- again -- the number of things we know can be formed naturally. The trend is pretty obvious, and if you're holding out on something coming up that can't be formed naturally then you'll probably be disappointed.
The enemies of Democracy are
The example of artificial insemination is a good example. When artificial insemination was first introduced there was a lot of outcry over it. Now the only major objection is from the Catholic Church. Others who still object do so out of side-effects such as the destruction of embryos rather than objecting to the process as a whole (which the Catholic Church does). And in a few years even the Catholics will likely be fine with it.
But at the same time, this sort of example isn't so great. It involves a direct application: people are much more willing to change their ethical and moral attitudes when they see the actual benefits of a new technology.
The general worry of poor treatment of science is a valid one. Sarah Palin railed against research involving "fruit flies" and John McCain complained about research about bear DNA, and neither of those even had any moral or ethical component to them. There's a very strong anti-science attitude in certain groups in the United States. Worse, it appears on both sides of the political spectrum (the anti-vaccination movement and much of the fringier elements of alternative medicine are very much on the left end of the political spectrum). Moreover, strongly negative attitudes about evolution and abiogenesis research have already won out in some Islamic countries. Look at Turkey for example which is a nominally secular country (indeed with disturbingly enforced secularism) and yet evolution isn't taught in schools and universities have trouble doing any research connected to evolution or abiogenesis. See for example http://scienceblogs.com/gregladen/2009/11/islamic_creationism_in_the_new.php for a quick summary of the current situation in the Islamic world. Moreover, Islamic creationists in Turkey have succeeded partially due to support and cooperation with Christian creationists in the United States. So it is possible for religious fanatics to really restrict this sort of thing: It has happened in other countries. Is it likely? Probably not. But it isn't impossible.
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.