It's life, Jim, but not as we know it...

owedtojoy

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Mitsui2

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That's pretty big news, all right. The list of planets that can theoretically support life just got a whole lot bigger, for one thing.
 

Delarivier

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This is incredibly exciting, particularly for extremophile enthusiasts like myself. It appears as if it has arsenate replacing phosphate in its DNA. Arsenic has similar chemistry to phosphate, so it was theoretically possible, but this is the first discovery of arsenic-based nucleic acids. Can't wait to download the original paper in Science.
 

Green eyed monster

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Calling it 'bacteria' may be wrong if it doesn't use DNA/RNA (with phosphorus), they might have to create a new classification (hell they might have to create a new classification system).

According to the Guardian article the micro-organism does use a DNA analogue (still carbon based) except that it incorporates Arsenic into it's DNA structure instead of Phosphorus (all DNA that we know uses phosphorus)... It can do this because the chemical properties of Arsenic and Phosphorus are similiar (in the same column on the periodic table).

Nasa unveils new life form: Bacteria that thrive on arsenic | Story tracker | Science | guardian.co.uk

Still very interesting if true however, this kind of substitution will make the possibility of silicon based lifeforms elsewhere in the Universe seem more feasible (and less theoretical only).

I wonder could that new DNA-analogue composition form a more complicated organism?
 
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Green eyed monster

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I watched more of the video...

The two scientists say two things of importance.

1. He doesn't think it likely that arsenic incorporated into the DNA could exist in a higher order lifeform (due to the characteristics of the orbitals).

2. She admits that the samples contained both phosphorus and arsenic so there was only some substitution taking place.

Might be a bit early to jump the gun here with labels like 'alien' and so on.
 

owedtojoy

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Yes, there is an element here of NASA justifying its existence, especially when there are budget cuts on the horizon. The Republicans are full of anti-science zombies who want vengance on NASA for the way it has tackled global warming.

Reminds me of the "life on Mars" news release of ten years ago, interesting but not as shattering as they made it out ... bit speculative.

Interesting also that a lot of science fiction speculated about life forms with silicon instead of carbon ... I even remember a Star Trek episode where Spock mind-melded with a rock creature who was killing miners on some planet.... the "ore" they were mining turned out to be its eggs ... or something like that. But no one thought of arsenic instead of phosphate!!

Ok, maybe a higher life form with this genetic make-up not possible .. but on a different planet?
 

fluffykontbiscuits

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Was reading about it on the BBC yesterday and its fascinating. There was a link on the left hand side of the site that lead to a report from last year and it was saying arsenic could be used in place of the basic six building blocks. Goes to show we dont know whats out there! ***cue X Files music *** ;)
 

SideysGhost

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I even remember a Star Trek episode where Spock mind-melded with a rock creature who was killing miners on some planet.... the "ore" they were mining turned out to be its eggs ... or something like that.
Ah, the episode with the immortal Bones line:

"Dammit Jim, I'm a doctor not a bricklayer!" :cool:
 

Green eyed monster

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Was reading about it on the BBC yesterday and its fascinating. There was a link on the left hand side of the site that lead to a report from last year and it was saying arsenic could be used in place of the basic six building blocks. Goes to show we dont know whats out there! ***cue X Files music *** ;)
Don't believe that, nothing can match the versatility of carbon (except in theory silicon) in it's role... It can form single, double and triple bonds and can link to many other molecules forming the backbones necessary for complex and sophisticated chemistry. No way would Arsenic be able to do what powerful Oxygen can do, nor Hydrogen either (the chemistry of hydrogen is NOTHING like the others), Sulphur either. Nitrogen, Phosphorus and Arsenic do have somewhat similiar chemistry (and yet Nitrogen and Phosphorus chemistry is not at all confused in the body but are very distinct) and this new organism is believed to use the substitution of P for Arsenic.

Substitution happens in other forms of biochemistry of course, in a radioactive contamination situation one of the main hazards is incorporation of Strontium 90 into Bone (instead of Calcium with which it shares similiar chemistry). I think in these situations you are generally looking in each column on the periodic table for a possible substitute.
 

slippy wicket

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Sorry to lower the tone of the conversation for a sec, but i bet there is a yank somewhere trying to work out a way to mate with it. ;)
 

Incitatus

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From what I gather, it is a a bacterium that lives off arsenic and has a completely different genetic structure to the rest of the earth's creatures, who all have DNA.
Have any tests been done on that “core Fianna Fáil voter” of popular mythology?

Obvious, I know...
 

Delarivier

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I had a long discussion with a chemist about this. We agreed that arsenate compounds have a very short half-life in water. There might be proteins stabilising a form of DNA containing arsenate rather than phosphate, but nucleotides (the building blocks of DNA) would be unlikely to be stable. The paper showed a gel with a band corresponding to the DNA; this could be cut out and analysed, maybe using mass spectroscopy to show if it really does contain arsenic.
 


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