[HN Gopher] Magnetism may have given life its molecular asymmetry
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Magnetism may have given life its molecular asymmetry
Author : rbanffy
Score : 90 points
Date : 2023-09-07 13:20 UTC (3 days ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| bluenose69 wrote:
| The field flips from time to time. I wonder how that works into
| the theory/tests.
| bombolo wrote:
| [dead]
| whatshisface wrote:
| > _Athavale noted that even if the crystallization process
| happened in 100 primordial lakes, Earth's magnetic field would
| ensure that they all produced precursors with the same handedness
| rather than a mixture._
|
| I don't get it... Every grain of sand has two sides, so why
| wouldn't the crystals be equally likely to form on a north pole
| as a south pole?
| gilleain wrote:
| The summary is (as far as i understand) :
|
| * They have shown that magnetic surfaces can prefererentially
| crystalise one handed form of an RNA precursor
|
| * The mechanism involves electron spin interacting with the
| chirality of the molecule
|
| What was not clear to me was whether they have shown that one of
| the handed forms would be more frequent than the other.
| cma wrote:
| > What was not clear to me was whether they have shown that one
| of the handed forms would be more frequent than the other
|
| Wouldn't "preferentially" do that?
| gilleain wrote:
| edit: my bad, i should yave read further - the suggestion is
| that the location on the Earth'a surface could influence the
| surface chirality.
|
| Well if you have a 'left handed' surface and a 'right handed'
| surface then the problem has just shifted to the molecule to
| the surface.
|
| To put it another way - what drives the asymmetry of the
| surfaces?
| eep_social wrote:
| IIUC, the magnetic field generated by earth's rotation.
| danwills wrote:
| What a fascinating idea! Never considered the idea that what
| hemisphere-of-the-earth life started-in could have influenced our
| molecular chirality!
|
| Does anyone else reckon that homo-chiral life could have some
| advantages? Ie life in-which either-molecular-chirality still
| works with all the biomechanics somehow.. If that is even
| possible?! I'm not saying it definitely is! Just a sci-fi-ish
| idea that I thought was interesting.
|
| Maybe this would be such a complex (and outside-the-attractor)
| problem that it would've taken a fair-few more billions of years
| for evolution to have a chance of finding? This might make it
| mostly off-the table for us (or even similar beings elsewhere-in-
| the-universe?) Our sun (and most stars) will most-likely have
| some crazy stuff going on by then?! I'm hoping we can explore
| something like this synthetically somehow if/when humans become
| space-faring, and that it can harden-without-fundamentally-
| changing the underlying organism (and is also something that can
| be inherited by their children too, assuming that it works
| well!).
| distortionfield wrote:
| > Does anyone else reckon that homo-chiral life could have some
| advantages?
|
| No idea, but this topic is explored a bit in the Expanse books.
| They note that the alien lifeforms found on Ilus have chirality
| different from those of earth, and explore the consequences of
| that a little bit. They do a pretty good job of building out
| the native alien life on the planet in the books, and the show
| touched on it a little as well.
| mensetmanusman wrote:
| There are species of ocean life that use the earth's magnetic
| field to find oxygen after they are newly alive.
|
| A small percentage go the wrong way for millennia and die
| immediately, but they pass along their generations gene when the
| magnetic field flips of the earth.
|
| Always found that fascinating to consider...
| marklgr wrote:
| Can't be natural selection, can it? Sheer luck?
| nradov wrote:
| Which species is that? The oxygen concentration in the ocean
| does vary a bit by region but a larva would have to travel a
| huge distance in any compass direction to get a significant
| difference.
| jdthedisciple wrote:
| Garden-path title [0] if I've ever seen one
|
| [0] https://en.wikipedia.org/wiki/Garden-path_sentence
| morcheeba wrote:
| That's really interesting. Chirality is one of the six
| indicators[1] we'll use to detect life on Titan when we land
| there in 2034. But Titan doesn't have its own magnetosphere;
| there is one from Saturn that shields the moon from radiation,
| but it's not consistent like it is on Earth. I wonder what we'll
| find!
|
| [1] https://iopscience.iop.org/article/10.3847/PSJ/abfdcf
| colanderman wrote:
| Wouldn't polar chiral molecules also be distinguishable
| magnetically simply because they are physically mirrored? Any
| movement across a magnetic field will cause a polar molecule to
| rotate opposite relative to its structure and dipole than how its
| enantiomer would.
| capitainenemo wrote:
| That's really fascinating. But does this mean that strong
| magnetic fields impact biological reactions in our body?
| capitainenemo wrote:
| Also, I guess similarly, is this one more concern for folks in
| the ISS in orbit (rapidly changing field) or beyond earth's
| field.
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