Asimov wrote about precisely this, and hypothesised, well, exactly this, in his essay “The asymmetry of life” in the collection “The Left Hand of the Electron” - in 1972 - right down to gamma ray chirality due to electron spin asymmetry affecting an initial randomly distributed population.
See pages 65-67 of the below (pdf pages, not book pages).
Asimov refers to a 1968 paper, and a Nature article [1] refers to a 1967 paper by other researchers, so it seems like it may have been a common hypothesis at the time. However, Asimov doesn't refer to cosmic rays like the original article, but the Nature article does.
This is absolutely incredible. I’ve never read Asimov beyond one or two short stories, now I feel compelled to read his grander works. What an insanely keen mind.
> Thiotimoline is a fictitious chemical compound conceived by American biochemist and science fiction author Isaac Asimov. It was first described in a spoof scientific paper titled "The Endochronic Properties of Resublimated Thiotimoline" in 1948. The major peculiarity of the chemical is its "endochronicity": it starts dissolving before it makes contact with water.
> Asimov went on to write three additional short stories, each describing different properties or uses of thiotimoline.
I bet that if they found out the opposite, that the current chirality is less prone to mutations from cosmic rays, we'll have an identical article which celebrates their finding, except that they would propose it's better to have less mutations.
They need to prove that increasing number of mutations is even a desirable property.
I wonder why the parent comment is downvoted. To a layman like me, it sounds completely reasonable.
Maintaining an exact copy of RNA/DNA through generations and generations is a real challenge, right? Loosening up the copying mechanisms to allow for more mistakes would probably be quite easy to achieve, if that was beneficial, right?
I’d be interested to hear what makes the idea wrong.
I’m no expert in the field and the only remotely relevant experience I have is a tiny amount of genetic algorithm programming at a rank amateur level.
I assume that making perfect replicas is the default way for a given type of life to dominate. Making “random copies” (an oxymoron) is not likely to result in domination of any individual type (of building block, single cell, or multi-cellular life). Making perfect copies allows a build-up of “winners”.
If that implies a very strong selection process for perfect copies, then after that a selection process for increased (but still small in aggregate) mutation rate would seem globally helpful.
I believe cancer is only a problem for us overly complex, multicellular organisms. Cancer happens when some of your cells go rogue, so you have to have at least two cells to get cancer.
The easy way to get asymmetry is the "winner takes all". Why we have 5 fingers? 6 is probably a good number too. Cartoon characters have 4 fingers and they seem to do fine. Why all 5 and not a mix?
The answer is that there was an old fish with 5 whatever in it's fins, and the offspring conquered the land and evolved and now we have 5 fingers. If a 4 whatever fish tries to do the same trick, it will face a strong competition an if the offspring ever reach the technological level to create a small country, we would nuke them from orbit.
Medlife Crisis, a cardiologist that makes educational YouTube videos[0], did a somewhat similar (and very very funny) talk about the chirality of of the human body, linking it to the chirality of DNA and beyond[1]
Plenty of mutations are already produced by faulty copying. This is how viruses mutate. An early organism would have very error-prone RNA copying. How would the cosmic rays, producing a tiny effect on top of this, be relevant at all? The author fails to explain this. The secret to chirality might simply be chance: once the machinery is running it can only understand its own chirality.
I believe the original paper’s authors are suggesting that the effect of cosmic rays on mutations might be enantioselective (meaning they effect molecules differently based on their chirality).
They do address this. Faulty copying is not biased (except towards mutations which help decrease it). DNA chirality is. Over the course of hundreds of millions of years, that tiny bias adds up to a significantly more successful organism.
I would be interested to see more explanation for why cosmic rays turn out to have a specific chirality-preference, and the actual proportion to which they do. The article seems very light on information on that point.
(Not OP) I read that earlier while trying to answer the same question, but it doesn't seem to explain the cosmic ray handedness. Am I missing something?
Really interesting. Tangentially related, this 2006 Astronomy Picture of the Day showing a render of cosmic rays coming down and the corresponding air showers is really illustrative [1]. These things happen millions of times per day. I'd love to see a more modern animation of it.
A pretty small effect, given that Earth has on net lost atmosphere over time there was less cosmic ray radiation on the surface back then then there is now. Which is in stark contrast to UV radiation which came in easily before the Great Oxygenation produced an ozone layer. LUCA, the last universal common ancestor, probably already had some oxygen resistance before then because UV radiation was always breaking up water molecules to produce tiny amounts of oxygen that it had to deal with. (Currently reading Oxygen by Nick Lane)
Interesting. SETI planned on identifying any left-handed chirality outside of Earth as a good indicator for life not formed on Earth as we haven't managed to find any on Earth yet.
Tangentially: I was told once the reason spiral staircases go the other way (in castles usually) is that when running upstairs with a sword you want to be able to use your right hand to kill anyone coming down the stairs.
As a side note you do turn left in the UK roads, so this rule is not universal.
Right, I think most staircases I've seen in castles have required you to go clockwise when ascending. This means the attacker's sword hand would be pretty constrained!
On a semi-related note, I wonder why, even though I'm right-handed, my left hand is considerably stronger than my right one or how common this phenomenon is.
Not sure how accurate it was or how well I remember it but I once read an article that explained that your higher dexterity hand/limb(s) requires more conscious effort to reach the the same level of muscle utilization as a side effect of more sensitive nerve endings used for dexterity. And further speculated that the higher dexterity limb worked the muscles slightly more efficiently which can lead to slightly more muscle development in the non-dominate limb to balance out overutilization/less-efficient non-dominant limb. Suppose to be true for both arms and legs. However they did note that it only takes a small workout bias between limbs to surpass the small possibly natural differences in limb strengths.
I usually carry baggage and things in my left hand in order to leave my right hand free. My grip strength is tremendously better with my left hand and I'm pretty sure that's the reason.
Partially that's a different distribution of muscle fiber but partially to how the muscles are anchored to the bone. They get more leverage but don't have the range of motion to throw rocks or spears long distances the way humans can.
Any asymmetric activity involving a moderate amount of exertion and repeated regularly would create a difference in strength between the sides of the body, so this could actually be an explanation. ;)
Point your right thumb along the purple DNA helix at the top of the article (either direction). Your right fingers curl in the direction the helix turns, so the purple helix is right-handed.
Now do the same with your left hand and the orange DNA helices. When your left thumb points along the helix, your left fingers curl in the direction the helix turns, so the orange helices are left-handed.
Thank you for explaining the convention (I've heard it before). How does that relate to "righthandedness" otherwise?
I was just (jokingly) pointing out how introducing conventions for right or left requires memorization of some silly rule like this. I'd much prefer if they used made-for-purpose topological terms instead of pretending how this somehow relates to a widely known concept.
Are there any simplified explanations for the asymmetry of the weak force driving the cosmic ray polarity that doesn't require extensive knowledge in physics?
ok someone didn't like this comment, lets see if I can make it better.
The article linked doesn't have a lot of detail, but i'm impressed that someone has pushed through the standard reflexive though that either chiral form was equally likely and recognised that actually the universal has handedness that could have influenced the outcome.
That's what I think is the stroke of genius here, not the conclusion, but the idea to consider other forms of handedness
eg.
as context in which the left or right forms might not actually be equivalent.
The reason I think this is genius, is it is a question anyone could have asked. Lots of us have probably thought about it at some point and summarily concluded it was not a question we were capable of exploring.
See pages 65-67 of the below (pdf pages, not book pages).
http://www.arvindguptatoys.com/arvindgupta/asimov-electron.p...