Mmmmh the fact that a protein attaches to another structure doesn't imply it was built with that structure 'in mind'.
Think of allergies. Random-generated antibodies eventually bind to molecules they've never encountered before. One might say, shit happens.
The fact that some anaerobic prokaryotic cells produced proteins that were compatible with foreign aerobic invaders, thus setting up/contributing to a symbiontic system, is simply Darwinian. Some other didn't, and didn't make it to eukaryotes.
Maybe you're right, I don't have a theory, if thinking that they might have receptors incompatible with carrier proteins isn't enough to make one. However, I don't really think I'll go any further in this discussion, as I have no evidence to answer basic questions:
1) How many cell divisions does it take male/ewe mtDNA to become undetectable? This is important to assess whether mitochondria get rapidly eliminated or slowly, steadily degrade and decrease in number.
2) Would mitochondria transplants from a somatic cell to one of another individual work? That could determine once and for all if an egg cell is a different environment than a somatic cell with respect to mitochondria (it is in 90% all other respects, actually).
3) Would the same happen with a family in-breeding? That'd help understand if there's an in-cell 'hystocompatibility' system which differs from individual to individual, has a hereditary basis, or doesn't differ at all.
I realize that if I don't have an experimental answer to these questions, I really can't say anymore than: "It just so happens that they die of 'natural' death. I don't really think they get killed."
1) It has been postulated (and is, I think, a necessary part of the prokaryote-decendant theory) that a lot of mitochondrial DNA was actually snarfed by the nucleus - support for this postulate is precisely the fact that you mentioned - the nucleus provides a lot of supporting proteins/enzymes/etc. to mitochondria.
Mmmmh, I'd rather see that in a symbiontic key. I don't think it's easy to demonstrate the eukaryotic nucleus actually transcribes snarfed mtDNA, if not for the fact that mtDNA codons and tRNA differ from those the nucleus has. IMHO, it's more likely that mytochondria originally were 'smart' aerobic bacteria that found a convenient environment within an anaerobic one. Only the ones that were compatible with host cell structures, and that were able to take advantage of them while producing enough ATP, eventually came to 'live' in it. It looks like a gradual, Darwinian event to me, much more like a 'coincidence' than a transfer of nucleic acid.
Therefore this possibility is not ruled, at least not by that argument.
Of course it isn't! I'm sorry if I looked too assertive, but I'm sure that we don't have enough data yet to rule out anything. I just meant to make my point and, as i said before, we'd really need to take a look at what is or is not in early embryos to start understanding.
(3) WHY are male mitochondria incapable of reproducing is exactly the question we are all hypothesizing about.
It isn't sufficient simply to say that they are (incapable) - of course they are, they're not present in Dolly!!!!! I'm simply trying to present one possibility (they get bashed by the other mitochondria).
... Which implies a positive action... But male (ewe's) mytochondria might just be unable to reproduce, which is different from 'being bashed out', as is being infertile from being killed before you ever have sex... The result, of course, is the same.
** Sorry - that's just a little dig. If you shoot my theory down in flames, I'm gonna show you don't have one...;-) **
I do have one, yet I can't really be sure it's the right one! My theory comes down to this: transplant mytochondria from a somatic cell to an unfecundated (or recently fecundated) egg--- the mytochondria won't be able to reproduce in that environment, although they won't be destroyed by anything else... They'll simply age and disappear (or brcome undetectable) because of their inability to reproduce and to maintain theirselves...
I don't really know much about this stuff, but apparently somebody/thing at SURAnet (server: mae-east.ibm.net, located Vienna, VA) is "causing packets to be lost" on their way to Frisco...
I had thought that the Mitochondria inside the spermatozoa were locked into a segment between the nucleus and the tail (sort of a pre-tail energy-generation region), so that they couldn't actually be injected into the egg anyway???...
Well, actually no one ever told me that happens, but why shouldn't it? Since the nucleus enters the cell intact, there's no obstacle to keep them from slipping in. Also, I seem too recall that, unlike with other mammal sperms, human male nuclei enter the egg with their tail still on. It eventually gets 'melted' by enzymes, and it's one example of the egg reacting to foreign structures. Another one is the male nucleus itself, which dissolves after having triggered the female one into completing meiosis.
Isn't it more likely that the female mitochondria are THEMSELVES recognising and destroying the male mitochondria?
I don't really think so. As I said before, mytochondria are not 'living things'. We have almost complete maps of mt genomes and there aren't any enzymes that could do such things. Mytochondria are not even self-sufficient when it comes to maintaining their membranes, exchanging ions and they lack some key enzymes for respiration (is that the right English word for their main function?). The fact itself that mytochondria relate to ancient prokaryotes is fascinating and certainly likely, but not yet proven. My hystology professor told me last year that there's still a circulating theory that there really aren't many mytochondria, but a single, long and crooked one that gets sliced so that it looks like many. Of course, this sounds at least exotic, but shows how little we know about that. If the key to male (in the case of Dolly, ewe's) mtDNA disappearing is in anyway related to the outnumbering of female mt's over male ones, it has to be related to the incapability to reproduce as female ones do.
It'd be also very interesting to know how much foreign mtDNA could be found in a 4-, 8-, 16-cell embryo. That'd allow our speculations to be proven or ruled out...
Mmmh, apparently the guys made it to Nature, so bow to my masters. Yet, I never trust people who try to assimilate the human brain to a machine, at least not to one that we yet know of.
Culture is so influent. It's so obvious to me that one would scan one object at a time when searching an array of items for a tiny detail.
That's the way you're told to read, for example, albeit differently among different cultures.
In languages using phonetic alphabets, one's told to scan letter by letter and wait for a space, then put the letter in a string and possibly check with one's linguistic database for matches.
If you're playing pool, however, and you're watching your ball go, you're paying attention to a lot more 'events' at a time. You follow the ball's path, estimate its direction before it bounces on other balls (and often I get to picture its course and 'draw' it on my current 'view'). But you'll find yourself also keeping record of what color the first ball you hit was, which balls are possibly heading straight into the holes and which are not, and so forth.
Again, play tennis and your eyes/brain will be analyzing ball speed, course, estimating the bounce and checking if the ball lands out... it happens often that you're aware that the balls out but move and hit it anyway. That's because orders to your muscles have already been sent, but it also means that your brain has both ruled the ball out and estimated its path. One of the two has probably occurred before the other, but it might probably be because the two processes were indipendent yet not equally difficult to 'compute'.
Bottom line, I'd say that the 'attention area' capable of being processed is small, so you're naturally prone to shift from one point to another because of the limited 'screen' you have. Yet, if details aren't too tiny, and don't require great resolution, like balls moving, a broader scope is enough to let you observe them all and analyze them more or less in a parallel fashion...
Uhm, it's late, here... I forgot to add that mitochondria incompatibility with the host egg environment might also be related to the differences in proteins/enzymes the mt's are 'accustomed' to.
And if the software brain can run within a really small computer case that can fit inside your skull, you can copy your mind to the machine, implant it into your freshly cloned body and be immortal!
Then you'll have to start worrying about psychiatrists of the Redmond school, of course, but I wouldn't recommend open source for your brain, either. And how about Active XX/XY? If your mother chooses Windows 3000 as an OS when you're born, you might feel a compelling urge to talk about your most intimate secrets whenever she asks, then pass out and reboot...
It's no big surprise also because one factor, I presume.
One is that every egg cell has to face the risk of being injected foreign mitochondria during normal fecondation. If I'm not wrong, the plasma membrane of spermatozoa locks to the egg's one and opens up upon fecondation, allowing the nucleus (and possibly the mitochondria that lie behind it) to flow in. Therefore, the egg is likely to be exposed to male mtDNA which will not appear in the grown animal. My guess is that male mtDNA, if injected, eventually disappears as mitochondria replication is not allowed in a foreign environment (the egg plasma is originally filled with female-only proteins). It could be that male mitochondria in the female egg are not able to exchange proteins or other components (such as membrane lypids, for which they're not entirely indipendent), thus 'dying' for lack of 'maintenance'.
The technical ability of Spielberg as a sci-fi, hi-tech movie maker supervised by a more cerebral, in-depth producer.
Looks promising, I mean, if only Kubrick had been able to actually supervise the making. Yet, I don't think of Spielberg only as a blockbuster wizard. Schindler's List and Saving Private Ryan weren't mere FX stunt-movies IMHO...
My real point is that no matter the encryption strength in an export program, there will be a backdoor for the U.S. government to walk through.
While only weaker security is allowed by law to be exported, I don't think it's stated anywhere in the U.S. code that the federal government must have its reserved backdoor.
Consider this in military terms: it's like exporting stealth fighter jets that are only 50% as undetectable as the original ones, yet putting a radio switch in them that will enable the U.S. to turn off the engines of the craft at will.
"Just in case our radars didn't pick it up..."
Not only would it be easy for federal agencies to crack into a foreign system running U.S. encryption, it's 100% sure that they will if they try!
As for domestic encryption, it would probably be too inconstitutional of the government to ban strong encryption from the streets. After all, it is regarded as a weapon, and U.S. citizens have the constitutional right to all fashions of exotic weapons...
If they really needed to get into your American 128+ -bit encryption, why bother cracking it, they might just come pay friendly visit, or tap your old analogic phone... (Ok, that's just a little too paranoid, but...)
I've sent a mail to CmdrTaco, asking for more coverage on the issue. Well, here it is, so I'll post the mail with a couple of thoughts (sorry, it's LONG):
As a/. author indicated before, an old CNN/IDG story (should be found here) confirms beyond any reasonable doubt that the NSA is involved with, and has authority over, any developing software that contains encryption of sort. The article hints that NSA makes arrogant, threatening use of U.S. encryption export laws in order to force companies to open 'reserved' backdoors in their software and/or to loosen their encryption.
Aside from that single key found in Windows, which might or might not be the actual backdoor for the NSA (IMHO, it all looks a bit too naive to be serious), it's guaranteed that one or more security holes exist in all apps created for the world market, i.e. 99.8% of all software around, from Sun's to AOL's. This is particularly fearsome to people and companies, like me, who are not American.
No software is 100% secure, I know, and the power and means of government agencies are enough to break into anything they really want to. We all know they're implicitly authorized to do anything, legal or not, to pursue their interests. Yet, this is not a matter of cracking into a drug dealers computer to trace down their bank accounts, it's not government vs. bad guys.
This is something pre-emptive, addressing good and bad guys alike, all over the world.
Software producers in the U.S. are bound to report to the government about each step they take in to security technology, and they're required to always keep a copy of the keys for Uncle Sam to easily walk in.
It's not all about security, though...
Companies are forced to hire demanding professionals to handle the relations with the NSA (this is also stated in the article), to delay their products because they haven't 'loosened up' enough, to strip away features from their products, and so forth.
It's all in the article, and it's a lot more frightening (to the security-concerned) and irritating (to simple home users like me) than one *hypothetical* backdoor key in Windows. For once, it's not a matter of Microsoft kissing up to the government, this is the government pushing down on *all* software producers alike to grant itself access to every kind of encryption capable, secure software available.
This is quite big, and IMHO it deserves some more attention. Please let me know what you think.
Thanks for taking the time to go through this long rant, hope it was worth it!
I agree with the last point, that the Web allows for publishing costs to be near-zero.
This means that an online editor won't have to refuse publishing a book because it lacks enough commercial potential to turn even slightly profitable.
An editor choosing to publish not-so-easy-to-read books, I assume, risks money and 'literary' reputation. Thanks to Web publishing, s/he could at least rest assured that economic losses won't be a big deal. Of course, that implies that smaller revenues should be expected.
Yet again, reputation could still be a good reason to filter books to publish.
Or, a company might be betting on ad revenues and writers' fees to make a profit, but I wouldn't call that a publishing company. That'd sound more like Usenet, where (more or less) anyone can coin their two cents. Only this time the 'messages' would get longer...
In conclusion, less expenses mean a greater ability for indipendent publishers to reach their market share, and cheaper products for the readers, be they good or bad pieces of literature.
In the long run, though, a screening of published works will be imperative for a publishing company to preserve their identity, thus their target market, and their reputation. The writers left out of the game, I'm afraid, will have to turn to Geocities or the like.
But let me recommend they first check the Terms of Service or they might wake up one day to find their works finally published with a Y! where their name should have been...
Slashdot Mirror
Mmmmh the fact that a protein attaches to another structure doesn't imply it was built with that structure 'in mind'.
Think of allergies. Random-generated antibodies eventually bind to molecules they've never encountered before. One might say, shit happens.
The fact that some anaerobic prokaryotic cells produced proteins that were compatible with foreign aerobic invaders, thus setting up/contributing to a symbiontic system, is simply Darwinian. Some other didn't, and didn't make it to eukaryotes.
Maybe you're right, I don't have a theory, if thinking that they might have receptors incompatible with carrier proteins isn't enough to make one. However, I don't really think I'll go any further in this discussion, as I have no evidence to answer basic questions:
1) How many cell divisions does it take male/ewe mtDNA to become undetectable? This is important to assess whether mitochondria get rapidly eliminated or slowly, steadily degrade and decrease in number.
2) Would mitochondria transplants from a somatic cell to one of another individual work? That could determine once and for all if an egg cell is a different environment than a somatic cell with respect to mitochondria (it is in 90% all other respects, actually).
3) Would the same happen with a family in-breeding? That'd help understand if there's an in-cell 'hystocompatibility' system which differs from individual to individual, has a hereditary basis, or doesn't differ at all.
I realize that if I don't have an experimental answer to these questions, I really can't say anymore than: "It just so happens that they die of 'natural' death. I don't really think they get killed."
1) It has been postulated (and is, I think, a necessary part of the prokaryote-decendant theory) that a lot of mitochondrial DNA was actually snarfed by the nucleus - support for this postulate is precisely the fact that you mentioned - the nucleus provides a lot of supporting proteins/enzymes/etc. to mitochondria.
;-) **
Mmmmh, I'd rather see that in a symbiontic key. I don't think it's easy to demonstrate the eukaryotic nucleus actually transcribes snarfed mtDNA, if not for the fact that mtDNA codons and tRNA differ from those the nucleus has. IMHO, it's more likely that mytochondria originally were 'smart' aerobic bacteria that found a convenient environment within an anaerobic one. Only the ones that were compatible with host cell structures, and that were able to take advantage of them while producing enough ATP, eventually came to 'live' in it. It looks like a gradual, Darwinian event to me, much more like a 'coincidence' than a transfer of nucleic acid.
Therefore this possibility is not ruled, at least not by that argument.
Of course it isn't! I'm sorry if I looked too assertive, but I'm sure that we don't have enough data yet to rule out anything. I just meant to make my point and, as i said before, we'd really need to take a look at what is or is not in early embryos to start understanding.
(3) WHY are male mitochondria incapable of reproducing is exactly the question we are all hypothesizing about.
It isn't sufficient simply to say that they are (incapable) - of course they are, they're not present in Dolly!!!!! I'm simply trying to present one possibility (they get bashed by the other mitochondria).
... Which implies a positive action... But male (ewe's) mytochondria might just be unable to reproduce, which is different from 'being bashed out', as is being infertile from being killed before you ever have sex... The result, of course, is the same.
** Sorry - that's just a little dig. If you shoot my theory down in flames, I'm gonna show you don't have one...
I do have one, yet I can't really be sure it's the right one! My theory comes down to this: transplant mytochondria from a somatic cell to an unfecundated (or recently fecundated) egg--- the mytochondria won't be able to reproduce in that environment, although they won't be destroyed by anything else... They'll simply age and disappear (or brcome undetectable) because of their inability to reproduce and to maintain theirselves...
Great tool!
I don't really know much about this stuff, but apparently somebody/thing at SURAnet (server: mae-east.ibm.net, located Vienna, VA) is "causing packets to be lost" on their way to Frisco...
I had thought that the Mitochondria inside the spermatozoa were locked into a segment between the nucleus and the tail (sort of a pre-tail energy-generation region), so that they couldn't actually be injected into the egg anyway???...
Well, actually no one ever told me that happens, but why shouldn't it? Since the nucleus enters the cell intact, there's no obstacle to keep them from slipping in. Also, I seem too recall that, unlike with other mammal sperms, human male nuclei enter the egg with their tail still on. It eventually gets 'melted' by enzymes, and it's one example of the egg reacting to foreign structures. Another one is the male nucleus itself, which dissolves after having triggered the female one into completing meiosis.
Isn't it more likely that the female mitochondria are THEMSELVES recognising and destroying the male mitochondria?
I don't really think so. As I said before, mytochondria are not 'living things'. We have almost complete maps of mt genomes and there aren't any enzymes that could do such things. Mytochondria are not even self-sufficient when it comes to maintaining their membranes, exchanging ions and they lack some key enzymes for respiration (is that the right English word for their main function?).
The fact itself that mytochondria relate to ancient prokaryotes is fascinating and certainly likely, but not yet proven. My hystology professor told me last year that there's still a circulating theory that there really aren't many mytochondria, but a single, long and crooked one that gets sliced so that it looks like many.
Of course, this sounds at least exotic, but shows how little we know about that.
If the key to male (in the case of Dolly, ewe's) mtDNA disappearing is in anyway related to the outnumbering of female mt's over male ones, it has to be related to the incapability to reproduce as female ones do.
It'd be also very interesting to know how much foreign mtDNA could be found in a 4-, 8-, 16-cell embryo. That'd allow our speculations to be proven or ruled out...
Getting always more intriguing!
Mmmh, apparently the guys made it to Nature, so bow to my masters. Yet, I never trust people who try to assimilate the human brain to a machine, at least not to one that we yet know of.
Culture is so influent. It's so obvious to me that one would scan one object at a time when searching an array of items for a tiny detail.
That's the way you're told to read, for example, albeit differently among different cultures.
In languages using phonetic alphabets, one's told to scan letter by letter and wait for a space, then put the letter in a string and possibly check with one's linguistic database for matches.
If you're playing pool, however, and you're watching your ball go, you're paying attention to a lot more 'events' at a time. You follow the ball's path, estimate its direction before it bounces on other balls (and often I get to picture its course and 'draw' it on my current 'view'). But you'll find yourself also keeping record of what color the first ball you hit was, which balls are possibly heading straight into the holes and which are not, and so forth.
Again, play tennis and your eyes/brain will be analyzing ball speed, course, estimating the bounce and checking if the ball lands out... it happens often that you're aware that the balls out but move and hit it anyway. That's because orders to your muscles have already been sent, but it also means that your brain has both ruled the ball out and estimated its path. One of the two has probably occurred before the other, but it might probably be because the two processes were indipendent yet not equally difficult to 'compute'.
Bottom line, I'd say that the 'attention area' capable of being processed is small, so you're naturally prone to shift from one point to another because of the limited 'screen' you have. Yet, if details aren't too tiny, and don't require great resolution, like balls moving, a broader scope is enough to let you observe them all and analyze them more or less in a parallel fashion...
Uhm, it's late, here... I forgot to add that mitochondria incompatibility with the host egg environment might also be related to the differences in proteins/enzymes the mt's are 'accustomed' to.
And if the software brain can run within a really small computer case that can fit inside your skull, you can copy your mind to the machine, implant it into your freshly cloned body and be immortal!
Then you'll have to start worrying about psychiatrists of the Redmond school, of course, but I wouldn't recommend open source for your brain, either.
And how about Active XX/XY? If your mother chooses Windows 3000 as an OS when you're born, you might feel a compelling urge to talk about your most intimate secrets whenever she asks, then pass out and reboot...
It's no big surprise also because one factor, I presume.
One is that every egg cell has to face the risk of being injected foreign mitochondria during normal fecondation. If I'm not wrong, the plasma membrane of spermatozoa locks to the egg's one and opens up upon fecondation, allowing the nucleus (and possibly the mitochondria that lie behind it) to flow in. Therefore, the egg is likely to be exposed to male mtDNA which will not appear in the grown animal.
My guess is that male mtDNA, if injected, eventually disappears as mitochondria replication is not allowed in a foreign environment (the egg plasma is originally filled with female-only proteins).
It could be that male mitochondria in the female egg are not able to exchange proteins or other components (such as membrane lypids, for which they're not entirely indipendent), thus 'dying' for lack of 'maintenance'.
The technical ability of Spielberg as a sci-fi, hi-tech movie maker supervised by a more cerebral, in-depth producer.
Looks promising, I mean, if only Kubrick had been able to actually supervise the making.
Yet, I don't think of Spielberg only as a blockbuster wizard.
Schindler's List and Saving Private Ryan weren't mere FX stunt-movies IMHO...
Mmmmh one thing is sure, should anything like that come out, backward compatibility is all but guaranteed.
I've never tried running, say, Baldur's Gate without a HD to store the 600+ MB cache, but I don't really think it'd be as enjoyable...
My real point is that no matter the encryption strength in an export program, there will be a backdoor for the U.S. government to walk through.
While only weaker security is allowed by law to be exported, I don't think it's stated anywhere in the U.S. code that the federal government must have its reserved backdoor.
Consider this in military terms: it's like exporting stealth fighter jets that are only 50% as undetectable as the original ones, yet putting a radio switch in them that will enable the U.S. to turn off the engines of the craft at will.
"Just in case our radars didn't pick it up..."
Not only would it be easy for federal agencies to crack into a foreign system running U.S. encryption, it's 100% sure that they will if they try!
As for domestic encryption, it would probably be too inconstitutional of the government to ban strong encryption from the streets. After all, it is regarded as a weapon, and U.S. citizens have the constitutional right to all fashions of exotic weapons...
If they really needed to get into your American 128+ -bit encryption, why bother cracking it, they might just come pay friendly visit, or tap your old analogic phone... (Ok, that's just a little too paranoid, but...)
I've sent a mail to CmdrTaco, asking for more coverage on the issue. Well, here it is, so I'll post the mail with a couple of thoughts (sorry, it's LONG):
/. author indicated before, an old CNN/IDG story (should be found here) confirms beyond any reasonable doubt that the NSA is involved with, and has authority over, any developing software that contains encryption of sort. The article hints that NSA makes arrogant, threatening use of U.S. encryption export laws in order to force companies to open 'reserved' backdoors in their software and/or to loosen their encryption.
As a
Aside from that single key found in Windows, which might or might not be the actual backdoor for the NSA (IMHO, it all looks a bit too naive to
be serious), it's guaranteed that one or more security holes exist in all apps created for the world market, i.e. 99.8% of all software around, from Sun's to AOL's. This is particularly fearsome to people and companies, like me, who are not American.
No software is 100% secure, I know, and the power and means of government agencies are enough to break into anything they really want to. We all know they're implicitly authorized to do anything, legal or not, to pursue their interests.
Yet, this is not a matter of cracking into a drug dealers computer to trace down their bank accounts, it's not government vs. bad guys.
This is something pre-emptive, addressing good and bad guys alike, all over the world.
Software producers in the U.S. are bound to report to the government about each step they take in to security technology, and they're required to always keep a copy of the keys for Uncle Sam to easily walk in.
It's not all about security, though...
Companies are forced to hire demanding professionals to handle the relations with the NSA (this is also stated in the article), to delay
their products because they haven't 'loosened up' enough, to strip away features from their products, and so forth.
It's all in the article, and it's a lot more frightening (to the security-concerned) and irritating (to simple home users like me) than one *hypothetical* backdoor key in Windows.
For once, it's not a matter of Microsoft kissing up to the government, this is the government pushing down on *all* software producers alike to
grant itself access to every kind of encryption capable, secure software available.
This is quite big, and IMHO it deserves some more attention. Please let me know what you think.
Thanks for taking the time to go through this long rant, hope it was worth it!
I agree with the last point, that the Web allows for publishing costs to be near-zero.
This means that an online editor won't have to refuse publishing a book because it lacks enough commercial potential to turn even slightly profitable.
An editor choosing to publish not-so-easy-to-read books, I assume, risks money and 'literary' reputation. Thanks to Web publishing, s/he could at least rest assured that economic losses won't be a big deal. Of course, that implies that smaller revenues should be expected.
Yet again, reputation could still be a good reason to filter books to publish.
Or, a company might be betting on ad revenues and writers' fees to make a profit, but I wouldn't call that a publishing company. That'd sound more like Usenet, where (more or less) anyone can coin their two cents. Only this time the 'messages' would get longer...
In conclusion, less expenses mean a greater ability for indipendent publishers to reach their market share, and cheaper products for the readers, be they good or bad pieces of literature.
In the long run, though, a screening of published works will be imperative for a publishing company to preserve their identity, thus their target market, and their reputation. The writers left out of the game, I'm afraid, will have to turn to Geocities or the like.
But let me recommend they first check the Terms of Service or they might wake up one day to find their works finally published with a Y! where their name should have been...
I know this could get tedious, but if you translate:
"Jesus, I've gotten so popular"
and cycle it a couple of times to Italian and back, you'll get something that could make for a good Gate$ quotation in the next Encarta:
Jesus, I have obtained, therefore popular.