Kevin's Watch

Ok Guys - we always seem to have great stuff on the start of the Universe here and we seem well endowed with bod's with exellent knowledge of both physics and maths, but what about the neglected area of biology. Can we pass muster here too, or will we be floundering like a mud skipper on a protean shore when faced with a challenging question in this area.

Whenever you hear talk of the origins of 'Life' on earth, it goes something like this (cue David Attenborough voice)

"In the primordial soup of molecules etc of the early world amino acids, purines, pyrimidines and other nucleic acid constituents form naturally (cue pictures of lightening striking the dark volcanic gloop of the primordial soup) and join together into chains of varying length and complexity. Proteins are formed, nucleic acids combine, replicate and separate and before long these proto-life like ingredients start to combine together - to act in symbiotic relationships, and we are but one step away from the formation of the first prokaryotic cell."
Well hang on I say; thats a whole lot of very complicated steps wrapped up into a few trite sentances.

Can anyone tell me - is this stuff known for sure. Is their any actual evidence that this is how it went. It seems a long way to me from a few random strings of amino acids and nucleic acids to a functioning cell. What lies in between. Is it known and if so can anyone tell me what it is?

I think someone around here is pretty expert in this area...certainly more than me.
what I do know is that they have created near-life in a lab. IIRC, it was RNA or something much like it, and it reproduced itself and cooperated.

Yeah, I think Plebe is who you want to talk to... or Plissken, I always get those two mixed

Anyways, it's not correct to view something as 'extremely complex'... if it's self sustaining, even momentarily, it becomes something viable. It's often something that chemists and physicists have to resort to get pesky molecules/particles: have an environment where something will happen, however infrequently, and it will happen. Allowing for sufficient time and energy, it will actually affect the system.

As far as evidence, we have the fossil record that shows us a progression from one-celled organisms to the multi-celled behemoths we have today. As far as more primitive organism, we got something around volcano vats at the bottom of the ocean which are not one-celled organisms and exist by converting what chemicals there are around it.

It seems to me that scientists have postulated "how life must have began", based on life's chemical nature, and searching for reactions that might lead to such chemicals. Then they set out to "recreate" the primordial soup, and prove their theory. But they have no idea if this is what really happened. Just that they have a plausible theory.

There's no "fossil record" for primordial life, or for the primordial soup out of which it theoretically has arisen. Without a time machine, it's hard to imagine that we could ever know what happened.

Something unpredictable, like a meteor crash, or a massive solar flare, or an alien visitation, might have occurred that triggered whatever had happened. If so, it's hard to imagine that we could ever piece the actual facts together.

wayfriend wrote:It seems to me that scientists have postulated "how life must have began", based on life's chemical nature, and searching for reactions that might lead to such chemicals. Then they set out to "recreate" the primordial soup, and prove their theory. But they have no idea if this is what really happened. Just that they have a plausible theory.

There's no "fossil record" for primordial life, or for the primordial soup out of which it theoretically has arisen. Without a time machine, it's hard to imagine that we could ever know what happened.

Something unpredictable, like a meteor crash, or a massive solar flare, or an alien visitation, might have occurred that triggered whatever had happened. If so, it's hard to imagine that we could ever piece the actual facts together.

Yep, if one could recreate delicious primordial soup in the laboratory, it only shows that there is one process by which it can come to pass, not that it is the process that did happen on our planet. And though it is unlikely that the soup would show up on the fossil record, its effects might.

That's Prebe you want. Or Xar for that matter. I think there's some stuff in the Close on this kind of thing.

I PM'd him, so lets see if he turns up. Otherwise I'll mail him. No peace for the wicked.

--A

Thanks Guys - I think I'll just wait and see if Plebe or Psst or Pixar show up; I wouldn't feel comfortable harangueing someone I 'didn't know' (via previous communication on the Watch) like a cold caller on the phone.

I'm not sure that anything more than base pair chains and possibly short amino acid chains have ever been demonstrated in the lab in expts to mimic early world conditions - certainly nothing capable of replication in the sense that DNA/RNA can manage. Whether protien chains with any life-like (alppha-helix?) stucture have been generated I don't know but I somehow doubt it. This avenue of research seemed to hit the headlines for a while and then to fizzle - unless it is ongoing as we speak, perhaps pushing the processees to new levels of advancement toward what can truly be recognised as life.

On that point alone of course we hit a thorny problem in that I don't believe to this day that it is truly sorted out as to what constitutes life and what does not. eg Viruses - living or non-living. Prion proteins - what are these little devils when they are at home?

IIRC fairly recently there was a news furore about a guy that had 'created life in the lab'. Turns out he had just taken a load of pre-existing viruses and recombined them in new ways to produce a new virus capable of replication (pretty irresposible stuff to me but there you go) - now this is hardly building new life from the drawing board up, so I think we have a ways to go yet before anyone gets the "It's Life Jim - But not as we know it" (aka the Frankenstein) award.

peter wrote: I'm not sure that anything more than base pair chains and possibly short amino acid chains have ever been demonstrated in the lab in expts to mimic early world conditions - certainly nothing capable of replication in the sense that DNA/RNA can manage.

Well, except for this:
www.livescience.com/3214-life-created-lab.html

A snippet:

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.

Well Vraith - that certainly constitutes work (and possibly advance) in the feild I was refering to above. I'm not sure it constitutes 'replication in the sense RNA/DNA can manage' but in fairness it's making a start.

I've got a few problems with the way the report is worded eg what are RNA enzymes, I thought all enzymes were protiens coced for by RNA in the transcription/translation part of (what was at one time) the 'central dogma' of molecular biology. There was a hypothesis at one stage called the 'One gene one enzyme' hypothesis, and if RNA can now constitute enzymes in their own right then I guess this must be history by now as well.

The last time I encountered these 'in the lab creation of the early stages of what could lead to life' expts, they were at the same stage that they had been two decades before in that their seemed to be nothing much new to report. If this is the advance of yet a decade or so furthur research then the reply as to how it is progressing would have to be "slowly" . We are not told in the report that the RNA was created from scratch although I think it was implied (not that this matters much - who said a jigsaw had to be piesed together in any given order), but most seriously I think from my point of view is that I'm not sure that what has been acieved here is much more significant than could be acieved with certain inorganic chemicles who might form crystal lattices from constituents in there surrounding media and then 'divide' at a given size.

Just how do we get from this rudimentary state to the organisational level of even the most simple of simple cellular organelles, let alone the first properly organised cell. Once this has been acieved then yes Darwinian evolution gives us a fantastically simple but effective theory for explaining all advancement from that point - but these early stages are problematic and I can't see that we've come close to nailing it. Biology is for me the area of scientific endevour where great steps remain to be taken in order to bring our knowledge levels up to that of physics and chemistry

peter wrote: Biology is for me the area of scientific endevour where great steps remain to be taken in order to bring our knowledge levels up to that of physics and chemistry

On the whole of your post, yes, there's still lots of stuff that's just hints and speculations. On the quoted part, I have a very strong suspicion/intuition just from trends/tendencies, that when [if] the answer comes it will actually come from those looking at the physics more closely than the bio part. Just a guess, though.

Vraith wrote:I have a very strong suspicion/intuition just from trends/tendencies, that when [if] the answer comes it will actually come from those looking at the physics more closely than the bio part. Just a guess, though.

You could well be right Vraith - very much a case of "Watch this space" I think.

I hope they haven't manufactured the end of the world! I hope that Immortalized RNA doesn't break out and start tearing everything, including us, apart to replicate itself! Heh

I'd like to see someone ceate life from scratch under any circumstances. Doesn't matter to me if they set things up the way they think it would have been in the primordial soup. Just make life.

Trouble is it gets very hard to define what life is at its fuzzy edges and the possibility that we would not recognise it as such if we did create it is a real one. Sometimes I get the feeling that the technical capabilities of this area of research (recombinant DNA etc) are ahead of its ability to forsee or control the results of its work and the analogy of a kid playing with a loaded gun springs to mind.

wayfriend wrote:Without a time machine, it's hard to imagine that we could ever know what happened....it's hard to imagine that we could ever piece the actual facts together.

The one thing that man will never know is the chemical composition of the stars. ---Auguste Comte, 19th century philosopher

This used to be emblematic of the type of scientific knowledge we'll "never know." Turns out, it was pretty easy to figure out the chemical composition of stars, despite this lack of imagination. All you need is a spectroscope, and knowledge of absorption lines.

Maybe we don't need a time machine to go into the past, but instead a crystal ball to see into the future.

As a biologist I really don't have much of a clue. "Something involving RNA" seems to be the prevailing theory atm. as far as I know.
What you want to Google is "Abiogenesis". I even think there is a half decent article on that in Wiki.

As far as hard evidence it is pretty tough to come by, hence a recreation of "something" in the lab is generally considered rather cool.

Edit: Not to worry. I did the Goggling for ya

Edit 2: Upon rereading, I hereby grant the article my Seal of Approval. It's an excellent and informative piece of work.

Prebe! It's about bloody time you showed up again.

--A

Thanks, but only in the non-flamable section at this point. But just you wait til I get the propper medication

Hahaha. It's not where you post, it's that you post. Welcome back.

--A

Thank you very much