8 ms·

Mirror life

145 points by ZeljkoS 8y ago

JetSetWilly 8y ago
> Mirror life presents potential dangers. For example, a chiral-mirror version of cyanobacteria, which only needs achiral nutrients and light for photosynthesis, could take over Earth's ecosystem due to lack of natural enemies, disturbing the bottom of the food chain by producing mirror versions of the required sugars. Some bacteria can digest L-glucose; exceptions like this would give some rare lifeforms an unanticipated advantage Does this have "great filter" implications? If it confers such a huge advantage for a prokaryote to have the opposite chirality, then it must be very unlikely for prokaryotes to evolve from scratch, as if it wasn't then something would have evolved to take advantage of this. It means that "the evolution of a simple prokaryote" has definitely only happened once.
- adrianN 8y ago
  I find it pretty unlikely that nothing would evolve to eat the mirror bacteria. edit: it might take some time though. Wood was indigestible for a long time, giving us coal deposits.
  - gilleain 8y ago
    Indeed, the premise is just wrong. It's not as if organisms cannot process biomolecules of the other handedness. There are enzymes called 'epimerases' and 'racemases' (https://en.wikipedia.org/wiki/Epimerase_and_racemase https://en.wikipedia.org/wiki/Epimerase_and_racemase) that convert stereocenters. While it's true that a mirror cell wall would be a barrier to being broken down, there's nothing that would fundamentally stop the evolution of a suitable degradation machinery for it.
  - macspoofing 8y ago
    >I find it pretty unlikely that nothing would evolve to eat the mirror bacteria. It may be the case that there is no easy jump for existing prokaryotes to handle mirror proteins. However in the 'worst case', predation would simply re-emerge from the original prokaryote via speciation ... but it may take a long time.
Sephr 8y ago
A mirrored chirality human is a major plot point of Daniel Suarez' "Change Agent" book.[1][2] It has interesting use in the story as mirrored chirality gives the character the ability to be immune to many toxins that would normally harm humans. [1]: https://en.wikipedia.org/wiki/Chemical_chirality_in_popular_fiction#Books https://en.wikipedia.org/wiki/Chemical_chirality_in_popular_... [2]: http://daniel-suarez.com/changeagentsynopsis.html http://daniel-suarez.com/changeagentsynopsis.html
- godelmachine 8y ago
  Cf.-> Arthur C Clarke’s “Technical Error” https://en.m.wikipedia.org/wiki/Technical_Error https://en.m.wikipedia.org/wiki/Technical_Error
- Aardwolf 8y ago
  What does he eat though?
- paulrouget 8y ago
  I wrote a short story about this: http://paulrouget.com/e/symmetry http://paulrouget.com/e/symmetry
- s_kilk 8y ago
  It's also a minor background detail in Mass Effect. If I recall correctly, Turian chirality is opposite that of humans, their food is poison to humans and vice versa, etc.
  - pavel_lishin 8y ago
    Quarians too, I believe.
- rjbwork 8y ago
  SPOILER! It's also a rather minor plot point in The Expanse series' 4th Novel, Cibola Burn. Some of the life on a new planet is bi-chiral, meaning it integrates both handednesses of proteins, amino acids, RNA bases and backbones, etc.
jamiethompson 8y ago
These mirror organisms would need a plethora of mirror microbes created for them if they were to be able to do things such as digest food. It would stand to reason then that some of these mirror good microbes would eventually evolve to become mirror bad microbes?
ocfnash 8y ago
I believe it is possible that our universe is not orientable, and so there may exist closed paths which, if followed, reverse orientation upon returning to the starting point. If you were right-handed and traversed such a loop, you would now be left-handed relative to everyone else, everyone would agree your heart was on the "right" side of your body etc. In fact even Atiyah touches on this idea (though without speculating that it might be a property of our universe). In Mind, Matter and Mathematics, he says: "When I was a student in Cambridge our mathematical society invited a distinguished professor of philosophy, C.D. Broad, to give us an evening lecture. He chose to talk on a problem which had much exercised Kant, the difference between right-handed gloves and left-handed gloves. After the lecture, over dinner, I diffidently suggested to Broad that, since Kant’s time, we mathematicians had a much better understanding of “handedness”, or chirality as scientists call it. We could even envisage a universe in which a left-handed glove could wander around to distant regions and return to fit your right-hand. "
- amelius 8y ago
  But wouldn't that mean that the universe has an edge, like a Mobius strip has an edge?
  - ocfnash 8y ago
    Good question, but no. For example the Klein bottle or real projective plane are closed surfaces containing no boundary. Incidentally the Mobius strip need not have a edge; you can leave out the boundary circle at the cost of having a non-compact space. This is exactly analogous to the difference between the closed and open intervals: [0, 1] vs (0, 1). In fact the projective plane can be obtained by taking a disc and glueing its boundary to that of the Mobius strip, which makes the two boundaries "cancel".
- paulrouget 8y ago
  I think left and right could not just be swapped seamlessly. Radioactive decay (beta) would behave differently. See Wu's experiment and parity violation.
Aardwolf 8y ago
> In this way, the creation of an Earth ecosystem without microbial diseases might be possible I'm not a microbiologist at all, but I don't think so. If big organisms can be mirrored, so will microbes. You need various good bacteria so already have to mirror those. If you've got the mirrored organisms with mirrored DNA and RNA, it's pretty certain virii and bacteria will form from it at some point. On another note, it's a shame we don't have a 4th dimension that we can rotate ourselves through to mirror ourselves, that would be interesting!
- kyberias 8y ago
  In principle you're right but that "at some point" is expected to be in the scale of millions of years. At least it would be very unlikely. This chiral world would give protection for all organisms to all the current pathogenic microbes. Many would have to evolve from scratch.
  - otakucode 8y ago
    Any distinction between 'pathogenic' and 'normal' microbes is necessarily filled with holes, and easily crossed.
jetrink 8y ago
"How would you like to live in Looking-glass House, Kitty? I wonder if they'd give you milk in there? Perhaps Looking-glass milk isn't good to drink." Through the Looking Glass, by Lewis Carroll
- nradov 8y ago
  Ironically we now know that regular cow milk isn't good for cats to drink.
crazygringo 8y ago
> The reverse sugars circulating in the chiral organism's body would be indigestible as far as normal bacteria are concerned, so any bacterium entering a chiral organism would simply starve to death. Interesting, this has been considered as a diet alternative but too expensive so far: > L-Glucose was once proposed as a low-calorie sweetener and it is suitable for patients with diabetes mellitus, but it was never marketed due to excessive manufacturing costs. [1] [1] https://en.wikipedia.org/wiki/L-Glucose https://en.wikipedia.org/wiki/L-Glucose
pavel_lishin 8y ago
Wasn't this fairly close to the premise in Peter Watts' Rifters series?
timothycubed 8y ago
This was used as a plot point in Neal Stephenson's novel 'Anathem'.
peter_d_sherman 8y ago
Fascinating! (Disclaimer: I am not a biologist or gene scientist.) This is sort of like the anti-matter concept in Physics, but applied to DNA and other living structures. Again, fascinating! This leads to another question, which is does light have chirality too? What about other waves in the electromagnetic spectrum? Does chirality affect a plant's ability to process sunlight? Is there a reverse-chirality version of sunlight? Oh, the questions and the possibilities! Great link for Hacker News!
- type0 8y ago
  I don't think this applies to quantum phenomena in that sense, light can have the so called spin but the concept is different. You can read about the interaction of such light with chiral molecules here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247477/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247477/
otakucode 8y ago
>In this way, the creation of an Earth ecosystem without microbial diseases might be possible. No. This is wrong on two fronts. First, there would be new diseases which are of the opposite chirality, obviously. There is no such thing as a real objective definition of 'disease'. There are only patterns which successfully reproduce themselves and those which do not. But whatever sort of environment constructed will essentially create its own diseases, which will infect and interfere with what we intend to create. Successful systems breed parasites. That's a truism in microbiology. Secondly, a microbe-free world would kill us. There are more bacterial cells in our body than there are cells with our own DNA. Our understanding of the importance of our microbiology to our lives is pretty meager, but it's enough to know that 'clean room' living would be nightmarish in the best case, but more likely just lethal. And if your intent is to only allow in the 'good' bacteria and viruses and funguses... that line doesn't really exist. Biology is too messy to enable those sorts of distinctions, really. Creating a 'mirror life' world might be pretty neat, but I don't think the benefit would be from eliminating microbial interference in our precious bodily fluids.

145 points by ZeljkoS 8y ago

> Mirror life presents potential dangers. For example, a chiral-mirror version of cyanobacteria, which only needs achiral nutrients and light for photosynthesis, could take over Earth's ecosystem due to lack of natural enemies, disturbing the bottom of the food chain by producing mirror versions of the required sugars. Some bacteria can digest L-glucose; exceptions like this would give some rare lifeforms an unanticipated advantage Does this have "great filter" implications? If it confers such a huge advantage for a prokaryote to have the opposite chirality, then it must be very unlikely for prokaryotes to evolve from scratch, as if it wasn't then something would have evolved to take advantage of this. It means that "the evolution of a simple prokaryote" has definitely only happened once.

adrianN 8y ago
I find it pretty unlikely that nothing would evolve to eat the mirror bacteria. edit: it might take some time though. Wood was indigestible for a long time, giving us coal deposits.
- gilleain 8y ago
  Indeed, the premise is just wrong. It's not as if organisms cannot process biomolecules of the other handedness. There are enzymes called 'epimerases' and 'racemases' (https://en.wikipedia.org/wiki/Epimerase_and_racemase https://en.wikipedia.org/wiki/Epimerase_and_racemase) that convert stereocenters. While it's true that a mirror cell wall would be a barrier to being broken down, there's nothing that would fundamentally stop the evolution of a suitable degradation machinery for it.
- macspoofing 8y ago
  >I find it pretty unlikely that nothing would evolve to eat the mirror bacteria. It may be the case that there is no easy jump for existing prokaryotes to handle mirror proteins. However in the 'worst case', predation would simply re-emerge from the original prokaryote via speciation ... but it may take a long time.

Sephr 8y ago

A mirrored chirality human is a major plot point of Daniel Suarez' "Change Agent" book.[1][2] It has interesting use in the story as mirrored chirality gives the character the ability to be immune to many toxins that would normally harm humans. [1]: https://en.wikipedia.org/wiki/Chemical_chirality_in_popular_fiction#Books https://en.wikipedia.org/wiki/Chemical_chirality_in_popular_... [2]: http://daniel-suarez.com/changeagentsynopsis.html http://daniel-suarez.com/changeagentsynopsis.html

godelmachine 8y ago
Cf.-> Arthur C Clarke’s “Technical Error” https://en.m.wikipedia.org/wiki/Technical_Error https://en.m.wikipedia.org/wiki/Technical_Error
Aardwolf 8y ago
What does he eat though?
paulrouget 8y ago
I wrote a short story about this: http://paulrouget.com/e/symmetry http://paulrouget.com/e/symmetry
s_kilk 8y ago
It's also a minor background detail in Mass Effect. If I recall correctly, Turian chirality is opposite that of humans, their food is poison to humans and vice versa, etc.
- pavel_lishin 8y ago
  Quarians too, I believe.
rjbwork 8y ago
SPOILER! It's also a rather minor plot point in The Expanse series' 4th Novel, Cibola Burn. Some of the life on a new planet is bi-chiral, meaning it integrates both handednesses of proteins, amino acids, RNA bases and backbones, etc.

jamiethompson 8y ago

These mirror organisms would need a plethora of mirror microbes created for them if they were to be able to do things such as digest food. It would stand to reason then that some of these mirror good microbes would eventually evolve to become mirror bad microbes?

ocfnash 8y ago

I believe it is possible that our universe is not orientable, and so there may exist closed paths which, if followed, reverse orientation upon returning to the starting point. If you were right-handed and traversed such a loop, you would now be left-handed relative to everyone else, everyone would agree your heart was on the "right" side of your body etc. In fact even Atiyah touches on this idea (though without speculating that it might be a property of our universe). In Mind, Matter and Mathematics, he says: "When I was a student in Cambridge our mathematical society invited a distinguished professor of philosophy, C.D. Broad, to give us an evening lecture. He chose to talk on a problem which had much exercised Kant, the difference between right-handed gloves and left-handed gloves. After the lecture, over dinner, I diffidently suggested to Broad that, since Kant’s time, we mathematicians had a much better understanding of “handedness”, or chirality as scientists call it. We could even envisage a universe in which a left-handed glove could wander around to distant regions and return to fit your right-hand. "

amelius 8y ago
But wouldn't that mean that the universe has an edge, like a Mobius strip has an edge?
- ocfnash 8y ago
  Good question, but no. For example the Klein bottle or real projective plane are closed surfaces containing no boundary. Incidentally the Mobius strip need not have a edge; you can leave out the boundary circle at the cost of having a non-compact space. This is exactly analogous to the difference between the closed and open intervals: [0, 1] vs (0, 1). In fact the projective plane can be obtained by taking a disc and glueing its boundary to that of the Mobius strip, which makes the two boundaries "cancel".
paulrouget 8y ago
I think left and right could not just be swapped seamlessly. Radioactive decay (beta) would behave differently. See Wu's experiment and parity violation.

Aardwolf 8y ago

> In this way, the creation of an Earth ecosystem without microbial diseases might be possible I'm not a microbiologist at all, but I don't think so. If big organisms can be mirrored, so will microbes. You need various good bacteria so already have to mirror those. If you've got the mirrored organisms with mirrored DNA and RNA, it's pretty certain virii and bacteria will form from it at some point. On another note, it's a shame we don't have a 4th dimension that we can rotate ourselves through to mirror ourselves, that would be interesting!

kyberias 8y ago
In principle you're right but that "at some point" is expected to be in the scale of millions of years. At least it would be very unlikely. This chiral world would give protection for all organisms to all the current pathogenic microbes. Many would have to evolve from scratch.
- otakucode 8y ago
  Any distinction between 'pathogenic' and 'normal' microbes is necessarily filled with holes, and easily crossed.

jetrink 8y ago

"How would you like to live in Looking-glass House, Kitty? I wonder if they'd give you milk in there? Perhaps Looking-glass milk isn't good to drink." Through the Looking Glass, by Lewis Carroll

nradov 8y ago
Ironically we now know that regular cow milk isn't good for cats to drink.

crazygringo 8y ago

> The reverse sugars circulating in the chiral organism's body would be indigestible as far as normal bacteria are concerned, so any bacterium entering a chiral organism would simply starve to death. Interesting, this has been considered as a diet alternative but too expensive so far: > L-Glucose was once proposed as a low-calorie sweetener and it is suitable for patients with diabetes mellitus, but it was never marketed due to excessive manufacturing costs. [1] [1] https://en.wikipedia.org/wiki/L-Glucose https://en.wikipedia.org/wiki/L-Glucose

pavel_lishin 8y ago

Wasn't this fairly close to the premise in Peter Watts' Rifters series?

timothycubed 8y ago

This was used as a plot point in Neal Stephenson's novel 'Anathem'.

peter_d_sherman 8y ago

Fascinating! (Disclaimer: I am not a biologist or gene scientist.) This is sort of like the anti-matter concept in Physics, but applied to DNA and other living structures. Again, fascinating! This leads to another question, which is does light have chirality too? What about other waves in the electromagnetic spectrum? Does chirality affect a plant's ability to process sunlight? Is there a reverse-chirality version of sunlight? Oh, the questions and the possibilities! Great link for Hacker News!

type0 8y ago
I don't think this applies to quantum phenomena in that sense, light can have the so called spin but the concept is different. You can read about the interaction of such light with chiral molecules here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247477/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247477/

otakucode 8y ago

>In this way, the creation of an Earth ecosystem without microbial diseases might be possible. No. This is wrong on two fronts. First, there would be new diseases which are of the opposite chirality, obviously. There is no such thing as a real objective definition of 'disease'. There are only patterns which successfully reproduce themselves and those which do not. But whatever sort of environment constructed will essentially create its own diseases, which will infect and interfere with what we intend to create. Successful systems breed parasites. That's a truism in microbiology. Secondly, a microbe-free world would kill us. There are more bacterial cells in our body than there are cells with our own DNA. Our understanding of the importance of our microbiology to our lives is pretty meager, but it's enough to know that 'clean room' living would be nightmarish in the best case, but more likely just lethal. And if your intent is to only allow in the 'good' bacteria and viruses and funguses... that line doesn't really exist. Biology is too messy to enable those sorts of distinctions, really. Creating a 'mirror life' world might be pretty neat, but I don't think the benefit would be from eliminating microbial interference in our precious bodily fluids.