Quote:

Life As We Know It Nearly Created in Lab Robert Roy Britt Editorial Director livescience.com – Sun Jan 11, 9:55 pm ET One of life's greatest mysteries is how it began. Scientists have pinned it down to roughly this: Some chemical reactions occurred about 4 billion years ago - perhaps in a primordial tidal soup or maybe with help of volcanoes or possibly at the bottom of the sea or between the mica sheets - to create biology. Now scientists have created something in the lab that is tantalizingly close to what might have happened. It's not life, they stress, but it certainly gives the science community a whole new data set to chew on. The researchers, at the Scripps Research Institute, created molecules that self-replicate and even evolve and compete to win or lose. If that sounds exactly like life, read on to learn the controversial and thin distinction. Know your RNA To understand the remarkable breakthrough, detailed Jan. 8 in the early online edition of the journal Science, you have to know a little about molecules called RNA and DNA. DNA is the software of life, the molecules that pack all the genetic information of a cell. DNA and the genes within it are where mutations occur, enabling changes that create new species. RNA is the close cousin to DNA. More accurately, RNA is thought to be a primitive ancestor of DNA. RNA can't run a life form on its own, but 4 billion years ago it might have been on the verge of creating life, just needing some chemical fix to make the leap. In today's world, RNA is dependent on DNA for performing its roles, which include coding for proteins. If RNA is in fact the ancestor to DNA, then scientists have figured they could get RNA to replicate itself in a lab without the help of any proteins or other cellular machinery. Easy to say, hard to do. But that's exactly what the Scripps researchers did. Then things went surprisingly further. 'Immortalized' Specifically, the researchers synthesized RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely. "Immortalized" RNA, they call it, at least within the limited conditions of a laboratory. More significantly, the scientists then mixed different RNA enzymes that had replicated, along with some of the raw material they were working with, and let them compete in what's sure to be the next big hit: "Survivor: Test Tube." Remarkably, they bred. And now and then, one of these survivors would screw up, binding with some other bit of raw material it hadn't been using. Hmm. That's exactly what life forms do ... When these mutations occurred, "the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture," the scientists report. The "creatures" - wait, we can't call them that! - evolved, with some "species" winning out. "It kind of blew me away," said team member Tracey Lincoln of the Scripps Research Institute, who is working on her Ph.D. "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting." Indeed. Knocking on life's door Lincoln's advisor, professor Gerald Joyce, reiterated that while the self-replicating RNA enzyme systems share certain characteristics of life, they are not life as we know it. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts," Joyce said in a statement. Joyce's restraint, clear also on an NPR report of the finding, has to be appreciated. He allows that some scientists familiar with the work have argued that this is life. Another scientist said that what the researchers did is equivalent to recreating a scenario that might have led to the origin of life. Joyce insists he and Lincoln have not created life: "We're knocking on that door," he says, "but of course we haven't achieved that." Only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life, Joyce said. In short, the molecules in Joyce's lab can't evolve any totally new tricks, he said.

http://news.yahoo.com/s/livescience/20090112/sc_livescience/lifeasweknowitnearlycreatedinlab;_ylt=AspUGV_ok8Vt1yhXFs3mcrIPLBIF

Impressive, but the explanation is incomplete. There is some conjecture that nanobes may reproduce using RNA. They are too small for DNA replication.

yes, good going for sure.

It is wrong to call "DNA the software of life". In analogy with computers it is more like a hardware with  embedded code similar to BIOS chip.

There was a paper published a few years ago that demonstrated self replication of peptides - these are just fragments of proteins. I'll see if I can dig it up. Here we are:

Commeyras A, Taillades J, Collet H, et al.
Dynamic co-evolution of peptides and chemical energetics, a gateway to the emergence of homochirality and the catalytic activity of peptides
ORIGINS LIFE EVOL B 34 (1-2): 35-55 FEB 2004

ALSO:

Lee DH; Granja JR; Martinez JA; Severin K; Ghadiri MR

Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA.

Nature 382: 525-8 (1996)

Abstract
The production of amino acids and their condensation to polypeptides under plausibly prebiotic conditions have long been known. But despite the central importance of molecular self-replication in the origin of life, the feasibility of peptide self-replication has not been established experimentally. Here we report an example of a self-replicating peptide. We show that a 32-residue alpha-helical peptide based on the leucine-zipper domain of the yeast transcription factor GCN4 can act autocatalytically in templating its own synthesis by accelerating the thioester-promoted amide-bond condensation of 15- and 17-residue fragments in neutral, dilute aqueous solutions. The self-replication process displays parabolic growth pattern with the initial rates of product formation correlating with the square-foot of initial template concentration.


The latter paper describing the peptide self synthesis was quite ikonoclastic back in the 90's. The peptide is a relatively simple 32 residue fragment, which means a sequence of 32 amino acids join to form a helix shape in this case.

This particular 32-unit chain is an alpha-helix, where hydrogen bonds between different amino acid residues cause the chain to helicize. Under experimental conditions, they were using peptides of 15 and 17 units length in a neutral aqueous solution.

As far as the 32 base peptide self replication, I think you'll agree that it's a long way from self replication from an organic soup. We have a system of catalysis where the two halfs of a peptide can be joined. Although it's a very useful step in understanding the development of the first life, we still have a 3000 piece jigsaw puzzle with perhaps 3 or 4 pieces in place.

A number of researchers are currently investigating the protein origin (enzyme precursors) rather than nucleic acid origin theories, which require a ribose based precursor to RNA.

I'm a bit out of touch with this research nowadays, so there have probably been many other developments since then.

It would be interesting to know the definition of life that is used as target for lab life creation experiments.

There is no special definition for labs. There is a general one for biology, but it is hardly universal. I think there is disagreement over whether viruses are alive. The definitions usually consists of a number of criteria that have to be met, like self replication, energy consumption etc.

freediver wrote on Jan 14^th, 2009 at 11:30am:

There is no special definition for labs. There is a general one for biology, but it is hardly universal. I think there is disagreement over whether viruses are alive. The definitions usually consists of a number of criteria that have to be met, like self replication, energy consumption etc.

I believe they really need universally accepted (by scientists) definition to test against to make the claim of a lab life form creation.

Isn't that really just semantics? It is experiments like these that make people question what life really is. It's the knowledge we gain that matters, not some arbitrary goal post.

IMHO Viruses are not alive. They are basically just strands of genetic information. They are not capable of self replication. They replicate only as a result of infecting a suitable host cell.

I don't think being parasitic rules out being alive. However I think the argument is that viruses themselves do not consume energy. They rely on the energy mechanisms of the host. However that is just an argument of proximity. All parasites rely on the energy obtained by the host in some way. They just step in at different places along the chain.

Semantics are necessary to avoid mutual misunderstanding when multiple claims are made as scientific explorers are only humans especially when patents are concerned. But of course it does not belittle the value of the knowledge gained.

Muso, I don't know about biological viruses. How do they replicate?

It will not cause misunderstanding between the scientists because they will go by the detailed description of what really happened, not by broad claims and the definition of life. Misunderstanding by the general public is inevitable. The reality is not likely to be black and white, alive vs inanimate. A definition will not solve that problem, only cover up the complexity of reality. Getting the public in on the debate over whether they have created life is a good thing. Spoonfeeding the public broad generalisations is a bad thing. Telling them there are simple answers when there aren't is a bad thing. If the general public understood it all, it wouldn't be cutting edge research.

tallowood wrote on Jan 14^th, 2009 at 12:04pm:

Muso, I don't know about biological viruses. How do they replicate?

Rather than explain it myself, here's a reference:

http://virology-online.com/general/Replication.htm

There is a bit more to it than just being parasitic. Parasites normally have an independent reproductive system, such as spores in the case of some bacteria. Viruses don't have any reproductive or metabolic structures. They don't even have cells or mitochondria.

Are cells, mitochondria, or penises a pre-requisite for life?

Here's one definition of the properties of life:

Conventional definition: The consensus is that life is a characteristic of organisms that exhibit all or most of the following phenomena:

Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature.
Organization: Being composed of one or more cells, which are the basic units of life.
Metabolism: Consumption of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
Growth: Maintenance of a higher rate of synthesis than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun (phototropism) and chemotaxis.
Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.

On another forum, I made a case that Martian rocks were living, based on all those criteria. Reproduction was when a piece of rock fell off and was eroded to form part of another consolidated deposit.  Of course I wasn't serious  ;D

freediver wrote on Jan 14^th, 2009 at 1:54pm:

Are cells, mitochondria, or penises a pre-requisite for life?

See my last post. With penises, you can be alive without one - you'd  just wish you were dead.  :D

Quote:

On another forum, I made a case that Martian rocks were living, based on all those criteria. Reproduction was when a piece of rock fell off and was eroded to form part of another consolidated deposit.  Of course I wasn't serious

What about growth?

You make a good point about how 'wishy-washy' the definition is. It doesn't take us far enough away from 'you know it when you see it'. I also think that definition is far too specific on some issues. I would toss out any reference to cells, as it is concievable that alien life forms will not be cell based. They would still be organised, though organisation itself takes us back to 'you know it when you see it'. I suspect they put that in to reject viruses. I would also toss out homeostasis. A single celled organism could be considered alive even if it could only live in a stable environment identical to it's internal conditions. Again, this comes down to 'you'd know it if you saw it'. The smaller the organism, the more trivial this criteria. Response to stimili is unnecessary. If something satisfied the other conditions, including adaptation, it would also satisfy this one.

The only time I have tried to used a definition was in an argument about the Great Barrier Reef. I am sick of journalists saying it is the largest living organism on earth. That is like saying that a herd of cows is a living organism. I would include something about discretisation or irreducability. That is, if something is alive, you can break it down into single organisms, but breaking it down further kills it.

I would also include death, on an individual basis.

freediver wrote on Jan 14^th, 2009 at 12:13pm:

It will not cause misunderstanding between the scientists because they will go by the detailed description of what really happened, not by broad claims and the definition of life. Misunderstanding by the general public is inevitable. The reality is not likely to be black and white, alive vs inanimate. A definition will not solve that problem, only cover up the complexity of reality. Getting the public in on the debate over whether they have created life is a good thing. Spoonfeeding the public broad generalisations is a bad thing. Telling them there are simple answers when there aren't is a bad thing. If the general public understood it all, it wouldn't be cutting edge research.

But how can scientists declare that artificial life form was created in a lab if they have different definitions of such event?

Muso, thanks for the link, I will read it later tonight.

The definition of a life form you gave sounds reasonable except may be for the "exhibit all or most", that is a bit to vague for my liking.

Quote:

But how can scientists declare that artificial life form was created in a lab if they have different definitions of such event?

How can someone say something is good if there are different definitions for what is good?

freediver wrote on Jan 14^th, 2009 at 3:08pm:

Quote: But how can scientists declare that artificial life form was created in a lab if they have different definitions of such event? How can someone say something is good if there are different definitions for what is good?

In fact many people argue about that, sometimes to the death. That's why scientist should be mindful about semantics ambiguity.

freediver wrote on Jan 14^th, 2009 at 2:10pm:

Quote: On another forum, I made a case that Martian rocks were living, based on all those criteria. Reproduction was when a piece of rock fell off and was eroded to form part of another consolidated deposit.  Of course I wasn't serious What about growth?

Growth of sediment layers increases over time as the organism 'swallows' particles wafted in by the Martian wind and consolidates them to form new layers of skin. Mars is alive, I tell you  :D

They are mindful of it. It's just that rather than getting hung up on a definition of life, the explain in detail what they actually did, and leave it up to others to decide whether it is life.

tallowood wrote on Jan 14^th, 2009 at 3:23pm:

freediver wrote on Jan 14th, 2009 at 3:08pm: Quote: But how can scientists declare that artificial life form was created in a lab if they have different definitions of such event? How can someone say something is good if there are different definitions for what is good? In fact many people argue about that, sometimes to the death. That's why scientist should be mindful about semantics ambiguity.

There isn't a scientist alive who would claim to have created life or even claimed to have nearly created life. They leave that for the freshly fertilised minds of journos  :D

Here's what the real Scientists had to say:

Self-Sustained Replication of an RNA Enzyme

An RNA enzyme that catalyzes the RNA-templated joining of RNA was converted to a format whereby two enzymes catalyze each other’s synthesis from a total of four oligonucleotide substrates. These cross-replicating RNA enzymes undergo self-sustained exponential amplification in the absence of proteins or other biological materials. Amplification occurs with a doubling time of about one hour, and can be continued indefinitely. Populations of various cross-replicating enzymes were constructed and allowed to compete for a common pool of substrates, during which recombinant replicators arose and grew to dominate the population. These replicating RNA enzymes can serve as an experimental model of a genetic system. Many such model systems could be constructed, allowing different selective outcomes to be related to the underlying properties of the genetic system.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Just a tad different from the journalistic report, no?

Here's an idea.

Why don't we go to Mars, and build some structures, wonders if you will, like stuff from the old days we have now we can't understand, and then go dump that RNA stuff all over Mars.

Eventually we might get intelligent life on there and they will spend all their time trying to work out the mysteries of the wonders and make secret societies and stuff.

And by the time they evolve in to intelligent life, we will totally be able to go visit other planets and stuff, this is billions of years away, so then we can be the aliens and go visit them and abduct them and stuff, just for fun, not to hurt them.

Because it is my idea I demand the rights to design the wonders to be placed on Mars.

freediver wrote on Jan 14^th, 2009 at 3:31pm:

They are mindful of it. It's just that rather than getting hung up on a definition of life, the explain in detail what they actually did, and leave it up to others to decide whether it is life.

Then they should be ok as long as they don't claim anything that doesn't have unambiguous definition.

Muso's thing about Mars reminded me of Arthur Conan Doyle's personage the great misanthropic professor Challenger(?)
Professor Challenger who proved that the planet Earth was in fact living organism by drilling into the earth convinced that it is a sentient being and that by doing so he will be the first person to alert it to mankind's presence. He awakened the giant creature, which then destroyed his drill rig and caused earthquakes, tsunamis and volcano eruptions all over the place.
This professor was literally beating other professors into pulp over scientific definitions. What a great scientific mind he had.  ;)

easel wrote on Jan 14^th, 2009 at 4:10pm:

Here's an idea. Why don't we go to Mars, and build some structures, wonders if you will, like stuff from the old days we have now we can't understand, and then go dump that RNA stuff all over Mars.

Mars is too dry and oxidising. In the recent Phoenix expedition, they even found magnesium perchlorate - not a very friendly environment.

Apart from being dry, it's very salty too, which high levels (up to 20% by mass) of calium and magnesium chlorides and bromides.

tallowood wrote on Jan 14^th, 2009 at 4:28pm:

.........Professor Challenger who proved that the planet Earth was in fact living organism by drilling into the earth convinced that it is a sentient being and that by doing so he will be the first person to alert it to mankind's presence. He awakened the giant creature, which then destroyed his drill rig and caused earthquakes, tsunamis and volcano eruptions all over the place. This professor was literally beating other professors into pulp over scientific definitions. What a great scientific mind he had.  ;)

Reminds me of James Lovelock and his Gaia hypothesis. What a great thinker he is. He's 90 this year, and still working. He's also a great proponent of nuclear power, and usually stuns audiences when he says that they can make the nuclear waste dump in his backyard as long as he can use the waste heat for domestic purposes.


http://en.wikipedia.org/wiki/Gaia_Hypothesis

Back in early 1950s Harold Urey and Stanley Miller used "spark and soup" to produce amino acids.
They passed mixtures of boiling water, ammonia, methane and hydrogen through "electric spark systems".

The media of the time described these as proof for the possibility of spontaneous generation of life on Earth.

http://en.wikipedia.org/wiki/Miller-Urey_experiment

Quote:

Apart from being dry, it's very salty too, which high levels (up to 20% by mass) of calium and magnesium chlorides and bromides.

I think there's a lot of salty places on earth too.

Think cold, salty and dry to the extent of dessicated, and such a low atmospheric pressure that water ice evaporates straight to vapour. At the highest temperatures encountered, water will boil, or it might exist as thin films within the soil particles. Either way, it has a freezing point to Boiling point range of about 2 Celsius Degrees at the most.

The soil (regolith) itself acts as a dessicant. The nearest environment on Earth would be a laboratory vacuum dessicator, with dessicants so oxidising that they chemically destroy anything vaguely organic that land in it.

You could almost use it as a steriliser.

But then - drill down into the depths of Mars, and you just never know what you might find.

My own opinion is that we'll find rock and ice/CO2 clathrate - maybe some supercritical CO2 - but no life. Some people that work for NASA are more optimistic than me - or at least they have to seem optimistic to get the funds.

Mars is the only planet in this solar system where you have the possibility of supercritical CO2 and hydrothermal systems in close proximity.

Supercritical CO2 dissolves organic molecules (like oil), so when you evaporate off the CO2, we have a possibility of blobs of organic material surrounded by water and nutrients in hydrothermal vents. Add clay minerals and we have the first cell like structures.

It sounds like an interesting environment for life to have evolved - but that's pure speculation.

It should be possible to find life bearing planets some day. Just look for the oxygen signature in the absorption spectrum.  Oxygen means photosynthesis. Oxygen and Earth like temperatures are totally un-natural for planets without life.

Biology and the Planetary Engineering of Mars