This is just silly. If there is one thing we've learned in recent years it's that everywhere there is energy and water on earth there is life feeding on that energy. Utilizing the energy stored in a mirror photosynthetic life form would be far less difficult than harassing the energy from deep sea ocean vents.
I mean fuck worst comes to worst you can harness energy super inefficently by gather the microbes up and burning them. Indeed, I suspect there are already bacteria that can metabolize these mirror cells (perhaps inefficently) and would quickly enter into symbiotic relationships with many ocean lifeforms.
It might be a catastrophe for whales and other large ocean going vegetarians but hardly the end of the world. Hell, as some scientists keep pointing out WE DON'T KNOW THEY DON'T ALREADY EXIST!! Our current detection mechanisms aren't really set up to look for mirror organisms.
Moreover, the idea that they would even manage to hold their own against non-mirror organisms is sketchy. Through mechanisms like bacterial gene swapping and incorporation of genes from viruses the non-mirror organisms benefit from a vast evolutionary economy of scale. Indeed, it might well be a simple economy of scale issue rather than any rarity in the production of new life that explains the dominance of the current chirality. Immunity to a few viruses isn't that big a deal compared with the jump start you can get sharing beneficial mutations (even extremely indirectly and rarely).
If abiogenesis is extremely unlikely (i.e. it's where most of the great filter lies) then it's not first-mover advantage or a fitness advantage (through a CP-violating weak-force effect). It's just that life is very unlikely to develop at all, so when it does develop on a planet it does so just once, and the chirality is random.
We could eat some of the same food. Fatty acids are achiral, as is glycerol. We could get energy out of the same wine or liquor, as ethanol is achiral. Sugars and proteins, of course, are a different story, as are vitamins.
Humans cannot digest L-glucose, but it tastes just as sweet to us as D-glucose (the normal kind).
Yeast can survive with D-alanine as their sole nitrogen source. Non-mirror amino acids are L.
As a previous commenter noted, however, what matters is not whether non-mirror predators can digest mirror cells, but rather whether they will (try to) eat them. Human phagocytes will eat almost anything not marked as "self", including iron filings, and kill what they eat by non-chiral chemical means (reactive oxygen species) which would be equally effective against mirror bacteria as they are against normal bacteria.
If we desired, we could design and evolve mirror phages to infect mirror bacteria. These phages would be harmless to non-mirror life since their genetic material would be unreadable by host ribosomes.
Read some Franklin Harold - that will splash a little cold water on your overheated fantasies. In short, "it takes a cell to make a cell." The ONLY way we can even approach our childish fantasy of "creating life" is by hacking together some monstrous DNA and sticking it in a living cell. Obviously this will not work with reversed DNA. We are no further along in "creating life" as an autopoeitic entity from scratch than we were fifty years ago.
Would it be possible in the first place for an organism to be able to absorb both 'ordinary life' and 'mirror life'? Sounds unlikely to me, the molecules are 'tuned' either way. We'd be as poisonous to them as they are to them.
And as ordinary life is so much more common than mirror-life, there is no chance it would survive in the wild with all that poison. This is probably the reason why there is only one chirality of life on earth, left-handed won the 'coin toss' and broke symmetry.
That soup must have not only been rare, but small. Small enough that one chirality could dominate in short enough a time that the other chirality wouldn't exist as well. I'm guessing it would require either extreme luck in a tiny tiny pool (large enough for only one archaea to form and leave) or a chiral catalyst.
IVV:This is like what I was getting at above. Whatever made the primordial soup develop the first chiral lifeform, it seems to have been really rare. (How long would it have taken the first chiral molecule to "colonize" the entire soup and crowd out newcomers? Billions of years? Millions? Thousands?)
Is the chilarity the same for isolated lifeforms, like those bacteria living in superheated pools of water?
As a thought experiment, I think it's really cool to imagine that, if mirror cells had evolved, what life on earth would be like now. We would essentially have two separate lines of evolution. They would have similar environmental pressures, including each other.
Science fiction novel idea: a MacGuffin changes the chirality of half the life forms on earth. Half the human population becomes alien to the other half, not able to interbreed or even eat the same food.
Thanks. I don't think any of those molecules is chiral - unless you count the "heptahydrate" business - and any asymmetries there are probably not biologically significant.
But the step taking us from nothing to the building blocks of life would have to be taken for both chiralities, before DNA. This is the evolutionary step I'm referring to, pre-life. Nothing needs to change chiralities, it's all in the "decide a chirality" step.
The initial chirality can be found down to simpler molecules than DNA. Since both chiralities are present in a general chemical process, one would assume that the conditions that started life down the path for left-handed proteins also are conducive to creating right-handed proteins in a pre-genomic environment.
So, it would appear that there is a filter here. I can think of a few possibilities:
Perhaps left-handed molecules have some inherent advantage over right-handed ones. Given what comes out of the chemical processes in drug manufacture, I doubt this.
Perhaps there's a first-mover advantage, and the left-handed molecules were lucky enough to form RNA first. They then crowded out the right-handed molecules. This may suggest that reintroducing mirror cells could pose a risk, but then again, when it comes to crowding out, we have the advantage in numbers.
Perhaps we just simply have absolutely no idea how life first formed, and it requires some extra cosmic catalyst that came (comes?) with a chirality.
However, mirror life never developed with our life, and there must be a reason.
You would have to develop more than a new mirror lifeform - it would have to have working photosynthesis from the start, which is very unlikely. There is no primordial soup of nutrients waiting to be picked up now, not like there was when life first started on earth.
This is just silly. If there is one thing we've learned in recent years it's that everywhere there is energy and water on earth there is life feeding on that energy. Utilizing the energy stored in a mirror photosynthetic life form would be far less difficult than harassing the energy from deep sea ocean vents.
I mean fuck worst comes to worst you can harness energy super inefficently by gather the microbes up and burning them. Indeed, I suspect there are already bacteria that can metabolize these mirror cells (perhaps inefficently) and would quickly enter into symbiotic relationships with many ocean lifeforms.
It might be a catastrophe for whales and other large ocean going vegetarians but hardly the end of the world. Hell, as some scientists keep pointing out WE DON'T KNOW THEY DON'T ALREADY EXIST!! Our current detection mechanisms aren't really set up to look for mirror organisms.
Moreover, the idea that they would even manage to hold their own against non-mirror organisms is sketchy. Through mechanisms like bacterial gene swapping and incorporation of genes from viruses the non-mirror organisms benefit from a vast evolutionary economy of scale. Indeed, it might well be a simple economy of scale issue rather than any rarity in the production of new life that explains the dominance of the current chirality. Immunity to a few viruses isn't that big a deal compared with the jump start you can get sharing beneficial mutations (even extremely indirectly and rarely).
It occurred to me last night that this may already have happened (dumping photosynthetic mirror-bacteria in the ocean). Maybe that's the great filter!
If abiogenesis is extremely unlikely (i.e. it's where most of the great filter lies) then it's not first-mover advantage or a fitness advantage (through a CP-violating weak-force effect). It's just that life is very unlikely to develop at all, so when it does develop on a planet it does so just once, and the chirality is random.
We could eat some of the same food. Fatty acids are achiral, as is glycerol. We could get energy out of the same wine or liquor, as ethanol is achiral. Sugars and proteins, of course, are a different story, as are vitamins.
Humans cannot digest L-glucose, but it tastes just as sweet to us as D-glucose (the normal kind).
Yeast can survive with D-alanine as their sole nitrogen source. Non-mirror amino acids are L.
As a previous commenter noted, however, what matters is not whether non-mirror predators can digest mirror cells, but rather whether they will (try to) eat them. Human phagocytes will eat almost anything not marked as "self", including iron filings, and kill what they eat by non-chiral chemical means (reactive oxygen species) which would be equally effective against mirror bacteria as they are against normal bacteria.
If we desired, we could design and evolve mirror phages to infect mirror bacteria. These phages would be harmless to non-mirror life since their genetic material would be unreadable by host ribosomes.
Ummm. Guys.
You are smoking hashish and loving the sights.
Read some Franklin Harold - that will splash a little cold water on your overheated fantasies. In short, "it takes a cell to make a cell." The ONLY way we can even approach our childish fantasy of "creating life" is by hacking together some monstrous DNA and sticking it in a living cell. Obviously this will not work with reversed DNA. We are no further along in "creating life" as an autopoeitic entity from scratch than we were fifty years ago.
Would it be possible in the first place for an organism to be able to absorb both 'ordinary life' and 'mirror life'? Sounds unlikely to me, the molecules are 'tuned' either way. We'd be as poisonous to them as they are to them.
And as ordinary life is so much more common than mirror-life, there is no chance it would survive in the wild with all that poison. This is probably the reason why there is only one chirality of life on earth, left-handed won the 'coin toss' and broke symmetry.
Mirror viruses evolve to infect mirror cells.
It sounds as though you need to look into: http://en.wikipedia.org/wik...
That soup must have not only been rare, but small. Small enough that one chirality could dominate in short enough a time that the other chirality wouldn't exist as well. I'm guessing it would require either extreme luck in a tiny tiny pool (large enough for only one archaea to form and leave) or a chiral catalyst.
But then how is the catalyst made?
If it's chance and chance alone, then that would mean that there must be a first mover advantage--perhaps creation of the chiral catalyst.
IVV:This is like what I was getting at above. Whatever made the primordial soup develop the first chiral lifeform, it seems to have been really rare. (How long would it have taken the first chiral molecule to "colonize" the entire soup and crowd out newcomers? Billions of years? Millions? Thousands?)
Is the chilarity the same for isolated lifeforms, like those bacteria living in superheated pools of water?
As a thought experiment, I think it's really cool to imagine that, if mirror cells had evolved, what life on earth would be like now. We would essentially have two separate lines of evolution. They would have similar environmental pressures, including each other.
Science fiction novel idea: a MacGuffin changes the chirality of half the life forms on earth. Half the human population becomes alien to the other half, not able to interbreed or even eat the same food.
Thanks. I don't think any of those molecules is chiral - unless you count the "heptahydrate" business - and any asymmetries there are probably not biologically significant.
Chirality is down to chance or the weak force - but probably chance.
But the step taking us from nothing to the building blocks of life would have to be taken for both chiralities, before DNA. This is the evolutionary step I'm referring to, pre-life. Nothing needs to change chiralities, it's all in the "decide a chirality" step.
The initial chirality can be found down to simpler molecules than DNA. Since both chiralities are present in a general chemical process, one would assume that the conditions that started life down the path for left-handed proteins also are conducive to creating right-handed proteins in a pre-genomic environment.
So, it would appear that there is a filter here. I can think of a few possibilities:
Perhaps left-handed molecules have some inherent advantage over right-handed ones. Given what comes out of the chemical processes in drug manufacture, I doubt this.
Perhaps there's a first-mover advantage, and the left-handed molecules were lucky enough to form RNA first. They then crowded out the right-handed molecules. This may suggest that reintroducing mirror cells could pose a risk, but then again, when it comes to crowding out, we have the advantage in numbers.
Perhaps we just simply have absolutely no idea how life first formed, and it requires some extra cosmic catalyst that came (comes?) with a chirality.
However, mirror life never developed with our life, and there must be a reason.
You would have to develop more than a new mirror lifeform - it would have to have working photosynthesis from the start, which is very unlikely. There is no primordial soup of nutrients waiting to be picked up now, not like there was when life first started on earth.