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From: Bob Casanova <nospam@buzz.off>
Newsgroups: talk.origins
Subject: Re: origin of biological chirality?
Date: Thu, 22 Aug 2024 07:02:00 -0700
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On Thu, 22 Aug 2024 09:16:04 +0200, the following appeared
in talk.origins, posted by nospam@de-ster.demon.nl (J. J.
Lodder):

>Bob Casanova <nospam@buzz.off> wrote:
>
>> On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
>> in talk.origins, posted by Ernest Major
>> <{$to$}@meden.demon.co.uk>:
>> 
>> >A study has found that lipid membranes can be selectively permeable to
>> >one or the other sugar or amino acid enantiomer. The study used membrane
>> >models inspired by the membranes of modern organisms, so is not directly
>> >relevant to abiogenesis. However it still raises the possibility that
>> >membrane selectivity was the source of chirality in biological 
>> >molecules. One possible issue is does this effect require chiral 
>> >membrane lipids; if so it only move the question of the origin of 
>> >chirality from sugars and amino acids to lipids.
>> >
>> ISTM that this is similar to the "matter/antimatter"
>> imbalance; neither is inherently more "natural" than the
>> other, but one became more prevalent. And IIRC, the m/am
>> imbalance is now assumed to be a matter of chance in the
>> original ratio. I could; of course, be mistaken in that;
>> it's been years since I followed it even casually.
>> >
>> >https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
>
>It isn't. The left-handed molecules can be converted into right-handed
>ones, and vica versa, by taking them apart and reassembling them.
>For matter/antimatter there is no such possibility.
>Disassembling doesn't help,
>because you cannot turn antiquarks into quarks.
> 
>Biological chirality is a triviality,
>the matter/antimatter imbalance is a deep problem.
>Where has all that antimatter gone?
>
OK, I get that. I was only commenting on the prevalence of
one form when neither seemed to be inherently preferred. Ron
corrected me on that; that there apparently *is* a preferred
chirality, at least as to biology.

I seem to remember reading, decades ago, that at least some
of the then-current thinking on the matter/antimatter
imbalance that there was once only a small imbalance, but
that mutual annihilation removed almost all of both, leaving
the current deficit of antimatter. Is that still the case?
>
-- 

Bob C.

"The most exciting phrase to hear in science,
 the one that heralds new discoveries, is not
 'Eureka!' but 'That's funny...'"

- Isaac Asimov