Nucleotides from space!

[Subduction Zone]

Wow! Two science threads started in one night. First the link:

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites | Nature Communications

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites

Abstract
The lack of pyrimidine diversity in meteorites remains a mystery since prebiotic chemical models and laboratory experiments have predicted that these compounds can also be produced from chemical precursors found in meteorites. Here we report the detection of nucleobases in three carbonaceous meteorites using state-of-the-art analytical techniques optimized for small-scale quantification of nucleobases down to the range of parts per trillion (ppt). In addition to previously detected purine nucleobases in meteorites such as guanine and adenine, we identify various pyrimidine nucleobases such as cytosine, uracil, and thymine, and their structural isomers such as isocytosine, imidazole-4-carboxylic acid, and 6-methyluracil, respectively. Given the similarity in the molecular distribution of pyrimidines in meteorites and those in photon-processed interstellar ice analogues, some of these derivatives could have been generated by photochemical reactions prevailing in the interstellar medium and later incorporated into asteroids during solar system formation. This study demonstrates that a diversity of meteoritic nucleobases could serve as building blocks of DNA and RNA on the early Earth.

Okay (hopefully the bold goes away) on another site I was debating once and talked about nucleotides forming naturally when I meant amino acids. A creationist ripped into me for that mistake. Now it turns out that it was not a mistake after all. All five DNA/RNA nucleotides have been found in carbonaceous chondrite meteorites. Even if they were not the source of our initial DNA/RNA it does show that these chemical form naturally too.

 

[Subduction Zone]

Okay, I could not remove the bold from my OP, I tired throwing in an extra [/b] but was ignored. I don't like being all "shouty". Sorry.

 

[Debater Slayer]

Okay, I could not remove the bold from my OP, I tired throwing in an extra [/b] but was ignored. I don't like being all "shouty". Sorry.

Fixed and demarcated the quote per Rule 7.

 

[Subduction Zone]

Fixed and demarcated the quote per Rule 7.

Thank you so much.

 

[sayak83]

Wow! Two science threads started in one night. First the link:

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites | Nature Communications



Okay (hopefully the bold goes away) on another site I was debating once and talked about nucleotides forming naturally when I meant amino acids. A creationist ripped into me for that mistake. Now it turns out that it was not a mistake after all. All five DNA/RNA nucleotides have been found in carbonaceous chondrite meteorites. Even if they were not the source of our initial DNA/RNA it does show that these chemical form naturally too.

Yes. In fact cosmic ray induced transformations of nucleotides and amino acids in meteorites have been proposed as a possible route for the preponderance of chiral asymmetry in life molecules.

 

[We Never Know]

Yes. In fact cosmic ray induced transformations of nucleotides and amino acids in meteorites have been proposed as a possible route for the preponderance of chiral asymmetry in life molecules.

Ultraviolet radiation can alter DNA so I'm sure it can alter many other things.

 

[JDMS]

Thanks for sharing this!

 

[exchemist]

Yes. In fact cosmic ray induced transformations of nucleotides and amino acids in meteorites have been proposed as a possible route for the preponderance of chiral asymmetry in life molecules.

That's something I didn't know - and would not have expected. How does chiral asymmetry come about as a result of cosmic ray effects?

 

[exchemist]

Wow! Two science threads started in one night. First the link:

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites | Nature Communications



Okay (hopefully the bold goes away) on another site I was debating once and talked about nucleotides forming naturally when I meant amino acids. A creationist ripped into me for that mistake. Now it turns out that it was not a mistake after all. All five DNA/RNA nucleotides have been found in carbonaceous chondrite meteorites. Even if they were not the source of our initial DNA/RNA it does show that these chemical form naturally too.

My first thought was that pyrimidine-related bases ought to be synthesised more readily than purine-related ones, as pyrimidine is a simpler molecule (one ring rather than two). But then I read that stability is also a factor (e.g. cytosine is unstable, apparently because of its amine group), so it's clearly more more complicated than I was thinking.

 

[sayak83]

That's something I didn't know - and would not have expected. How does chiral asymmetry come about as a result of cosmic ray effects?

Cosmic Rays May Explain Life’s Bias for Right-Handed DNA
This is more recent research on ground based cosmic ray effect. The idea is that these effects are even stronger in space....

Cosmic Rays May Explain Life’s Bias for Right-Handed DNA
They started from the fact that cosmic ray showers, like DNA strands, have handedness. Physical events typically break right as often as they break left, but some of the particles in cosmic ray showers tap into one of nature’s rare exceptions. When the high energy protons in cosmic rays slam into the atmosphere, they produce particles called pions, and the rapid decay of pions is governed by the weak force — the only fundamental force with a known mirror asymmetry. Pions slamming into the atmosphere produce showers of particles including electrons and their heavier siblings, muons, all of which are equipped by the weak force with the same chiral magnetic orientation relative to their path. The particles bounce around as they streak through the atmosphere, Globus said, but overall they tend to keep their preferred chirality when they slam into the ground.

Interestingly organics from space have chiral asymmetry built in.
https://www.chemistryworld.com/news...t-origins-of-lifes-asymmetry-/1010379.article
George Cooper and Andro Rios from Nasa’s Ames Research Center in California analysed samples from 4.5 billion-year-old carbonaceous meteorites, which show some of the earliest chemistry in the solar system. When they isolated various sugar acids and sugar alcohols they found large excesses of the right handed, or d, enantiomers of most of these compounds, compared with the l mirror image form. ‘Any excess is unusual because most non-biological laboratory syntheses produce equal amounts of any mirror-image pair,’ explains Cooper.

 

[exchemist]

Cosmic Rays May Explain Life’s Bias for Right-Handed DNA
This is more recent research on ground based cosmic ray effect. The idea is that these effects are even stronger in space....

Cosmic Rays May Explain Life’s Bias for Right-Handed DNA
They started from the fact that cosmic ray showers, like DNA strands, have handedness. Physical events typically break right as often as they break left, but some of the particles in cosmic ray showers tap into one of nature’s rare exceptions. When the high energy protons in cosmic rays slam into the atmosphere, they produce particles called pions, and the rapid decay of pions is governed by the weak force — the only fundamental force with a known mirror asymmetry. Pions slamming into the atmosphere produce showers of particles including electrons and their heavier siblings, muons, all of which are equipped by the weak force with the same chiral magnetic orientation relative to their path. The particles bounce around as they streak through the atmosphere, Globus said, but overall they tend to keep their preferred chirality when they slam into the ground.

Interestingly organics from space have chiral asymmetry built in.
https://www.chemistryworld.com/news...t-origins-of-lifes-asymmetry-/1010379.article
George Cooper and Andro Rios from Nasa’s Ames Research Center in California analysed samples from 4.5 billion-year-old carbonaceous meteorites, which show some of the earliest chemistry in the solar system. When they isolated various sugar acids and sugar alcohols they found large excesses of the right handed, or d, enantiomers of most of these compounds, compared with the l mirror image form. ‘Any excess is unusual because most non-biological laboratory syntheses produce equal amounts of any mirror-image pair,’ explains Cooper.

That's very interesting indeed. I had not realised the weak interaction was handed in this way. I was dimly aware of symmetry breaking in physics but had never bottomed out what it is and where it arises.

But I see there are two different ideas: one that right-handed RNA and DNA might be fractionally more susceptible to mutation (and hence able to evolve faster via natural selection) and another idea that L amino acids and D sugars might be slightly more stable than the other enantiomer.

The speculative hypothesis I had previously come across was Earth-based: the idea that the faces of some crystals exhibit chirality and that maybe these had been an adsorption substrate for synthesis of complex organic molecules. But the finding that these molecules in space and are biased towards the same handedness we see in terrestrial biology seems to point to a more general and fundamental mechanism at work.

 

[Kenny]

Wow! Two science threads started in one night. First the link:

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites | Nature Communications



Okay (hopefully the bold goes away) on another site I was debating once and talked about nucleotides forming naturally when I meant amino acids. A creationist ripped into me for that mistake. Now it turns out that it was not a mistake after all. All five DNA/RNA nucleotides have been found in carbonaceous chondrite meteorites. Even if they were not the source of our initial DNA/RNA it does show that these chemical form naturally too.

WOW! Very interesting! I am always amazed at the creative diversity and the propelling power God has placed into effect and how it drives everything into purpose.

Thanks for sharing. There is so much more (as the other science thread suggested) that we still need to discover.

 

[exchemist]

WOW! Very interesting! I am always amazed at the creative diversity and the propelling power God has placed into effect and how it drives everything into purpose.

Thanks for sharing. There is so much more (as the other science thread suggested) that we still need to discover.

In this case you might think that God elected to operate the weak interaction in a symmetry breaking manner - and all the rest then followed naturally.

 

[Kenny]

In this case you might think that God elected to operate the weak interaction in a symmetry breaking manner - and all the rest then followed naturally.

I might... but I think I won't. I think things are so supernatural that we just think it is natural.

 

[sayak83]

That's very interesting indeed. I had not realised the weak interaction was handed in this way. I was dimly aware of symmetry breaking in physics but had never bottomed out what it is and where it arises.

But I see there are two different ideas: one that right-handed RNA and DNA might be fractionally more susceptible to mutation (and hence able to evolve faster via natural selection) and another idea that L amino acids and D sugars might be slightly more stable than the other enantiomer.

The speculative hypothesis I had previously come across was Earth-based: the idea that the faces of some crystals exhibit chirality and that maybe these had been an adsorption substrate for synthesis of complex organic molecules. But the finding that these molecules in space and are biased towards the same handedness we see in terrestrial biology seems to point to a more general and fundamental mechanism at work.

Yes. That is why the field is so interesting. Lots of interesting phenomena mutually affecting each other and the final outcome...life itself.

 

[Subduction Zone]

WOW! Very interesting! I am always amazed at the creative diversity and the propelling power God has placed into effect and how it drives everything into purpose.

Thanks for sharing. There is so much more (as the other science thread suggested) that we still need to discover.

You are welcome. This also is a small step into understanding abiogenesis. One thing that should comfort creationists that keep denying science only to see more and more evidence against their literalistic beliefs is that if a God exists this tells them more about how God made the world. There is no need to demand that Genesis needs to be taken literally.

 

[Kenny]

You are welcome. This also is a small step into understanding abiogenesis. One thing that should comfort creationists that keep denying science only to see more and more evidence against their literalistic beliefs is that if a God exists this tells them more about how God made the world. There is no need to demand that Genesis needs to be taken literally.

Hmmm... I don't deny science like atheists deny God.

 

[Subduction Zone]

Hmmm... I don't deny science like atheists deny God.

How could atheists deny God? That they do not believe appears to be God's fault.

 

[Revoltingest]

Wow! Two science threads started in one night. First the link:

Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites | Nature Communications



Okay (hopefully the bold goes away) on another site I was debating once and talked about nucleotides forming naturally when I meant amino acids. A creationist ripped into me for that mistake. Now it turns out that it was not a mistake after all. All five DNA/RNA nucleotides have been found in carbonaceous chondrite meteorites. Even if they were not the source of our initial DNA/RNA it does show that these chemical form naturally too.

Cthulhu put them there.
Some would say that God did,
but there's no evidence for that.

 

[Father Heathen]

Hmmm... I don't deny science like atheists deny God.

It's not denial. Their lack of belief is due to inadequate evidence. Belief that's sincere isn't a choice.