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I'm not buying the idea that simply having mirrored proteins is enough of an advantage for an organism that it would be able to completely out-compete the major

splat 16y ago
I agree. It would seem to me that if such organisms had such a big advantage in the wild they should have already evolved independently.
- ptpu 16y ago
  Note though, this would be really hard to evolve. As an analogy, the photosynthetic center RuBisCO is fairly wasteful, so any organism that can improve on RuBisCO would have a huge advantage. Only problem is RuBisCO is not easily evolvable (like brittle code), thus we don't know of any improvements although they are quite possible theoretically.
- Jach 16y ago
  Evolution doesn't seek out advantages, it just happens statistically that changes which carry advantages have more probability of rising to fixation within a species. Plus as ptpu touched on (and I'd wager he's more knowledgeable than I am) it's probably hard to even get the necessary mutations let alone having them stick around, or the species lasting long enough, etc.
stcredzero 16y ago
I'm not buying the idea that simply having mirrored proteins is enough of an advantage for an organism that it would be able to completely out-compete the majority of already existing natural organisms. By having mirrored proteins and sugars, such organisms would have no predators or parasites. This condition -- having no natural predators and parasites -- has been replicated many times through the dislocation of species through human transport. Often the result is that such a species is at a huge advantage, much to the detriment of the environment. These are called "Invasive Species." (Asian Carp, anyone? Brown Snakes in Hawaii? Kudzu? Rabbits in Australia?) Mirrored proteins and sugars would be much worse, since it would be exceedingly hard to evolve an ability to decompose these. I imagine that would happen eventually, but it would take such a long time, our environment would be in shambles and we'd be all long dead.
- Palomides 16y ago
  perhaps I'm just showing my ignorance, but I don't know any examples of invasive bacteria to trust that they'd be a problem in the same way, afaik predator/prey/competition is way more complicated at the micro level.
  - stcredzero 16y ago
    but I don't know any examples of invasive bacteria to trust that they'd be a problem in the same way Actually, that makes this even more dangerous. Normally there isn't much scope for invasive species of bacteria precisely because they've been around for a very long time and because they're everywhere. Odds are something has already evolved to eat something else that's similar. Mirror proteins break this. All of a sudden, nothing can eat these new organisms and survive for very long. It would be something unprecedented.
avdempsey 16y ago
I think evolutionary humility is a great thing to be reminded of, thank you Palomides. What's interesting to me is, an organism wouldn't have to out-compete the majority of already existing natural organisms to end the world, it "only" need replace the base of the ocean ecosystem. If a new form of bacteria killed all of the krill and plankton it would surely have grave consequences.

splat 16y ago

I agree. It would seem to me that if such organisms had such a big advantage in the wild they should have already evolved independently.

ptpu 16y ago
Note though, this would be really hard to evolve. As an analogy, the photosynthetic center RuBisCO is fairly wasteful, so any organism that can improve on RuBisCO would have a huge advantage. Only problem is RuBisCO is not easily evolvable (like brittle code), thus we don't know of any improvements although they are quite possible theoretically.
Jach 16y ago
Evolution doesn't seek out advantages, it just happens statistically that changes which carry advantages have more probability of rising to fixation within a species. Plus as ptpu touched on (and I'd wager he's more knowledgeable than I am) it's probably hard to even get the necessary mutations let alone having them stick around, or the species lasting long enough, etc.

stcredzero 16y ago

I'm not buying the idea that simply having mirrored proteins is enough of an advantage for an organism that it would be able to completely out-compete the majority of already existing natural organisms. By having mirrored proteins and sugars, such organisms would have no predators or parasites. This condition -- having no natural predators and parasites -- has been replicated many times through the dislocation of species through human transport. Often the result is that such a species is at a huge advantage, much to the detriment of the environment. These are called "Invasive Species." (Asian Carp, anyone? Brown Snakes in Hawaii? Kudzu? Rabbits in Australia?) Mirrored proteins and sugars would be much worse, since it would be exceedingly hard to evolve an ability to decompose these. I imagine that would happen eventually, but it would take such a long time, our environment would be in shambles and we'd be all long dead.

Palomides 16y ago
perhaps I'm just showing my ignorance, but I don't know any examples of invasive bacteria to trust that they'd be a problem in the same way, afaik predator/prey/competition is way more complicated at the micro level.
- stcredzero 16y ago
  but I don't know any examples of invasive bacteria to trust that they'd be a problem in the same way Actually, that makes this even more dangerous. Normally there isn't much scope for invasive species of bacteria precisely because they've been around for a very long time and because they're everywhere. Odds are something has already evolved to eat something else that's similar. Mirror proteins break this. All of a sudden, nothing can eat these new organisms and survive for very long. It would be something unprecedented.

avdempsey 16y ago

I think evolutionary humility is a great thing to be reminded of, thank you Palomides. What's interesting to me is, an organism wouldn't have to out-compete the majority of already existing natural organisms to end the world, it "only" need replace the base of the ocean ecosystem. If a new form of bacteria killed all of the krill and plankton it would surely have grave consequences.