Are you sure they're not suggesting a possibility and exploring the potential consequences?
Perhaps you could give an example?
First off, i simply could not undertsand the directions about the quotes(by no means your fault! thanks alot for the help).. i feel like im literrally stupid, i did programmign in college and right now i just cant "get it" for one reason or another...I'll just put your reply first then mine to that with a fair bit of space between..sorry, and thanks again
they actaully specifially say" The most parsimonious explanation
of this observation is that Topo IA was present in the last common ancestor of all
Archaea and was lost in Thaumarchaea"
The last common ancestor? see, there not talking about an analouge or a simlpler protein, there talking of topo being in the last common ancestor?
to me, that is irreconcilable(for now) with what i know about evoluiton!
Who do you mean, specifically?
Who has said that a particular enzyme and associated machinery appeared at exactly the same time as it was required?
Its not that there saying it, its that there is no solution by evolutions mechanisms, becuase as soon as it is needed, it must be there, otherwise, the cell wouldn't have gotten to where it is now.
If we look backwards, your right we cant tell a whole lot about that speculated time in history, but we can say, if evolution works the way we think, then topo MUST have been there the first time dna supercoied(as is suggested for archea!), and that is just...i cant yet get my head around such a statement. Again, this is not even discussing the fact that any TOPO or Gyarase simply cant be much "simpler", it must cut dna with its "pincers", otherwise(for the first cell needing it) its game over.
And of course I am skipping over the fact (and so are ALL these papers) that TOPO's are regulated and somehow brought to the right place by other proteins, then of course we have to have an energy source, and a binding sight...and the first time a cell with double stranded DNA had this probelm, all this had to be there by blind chance and "selection"?
hmmm, not convincing as of yet.
of course those sites could theoretically have been there from the "co opted proteins", but that is specualtion of course. Not to mention that it would have to arrive on the scene at just the right time in the cell cycle!
therefore if it was somehow adjusted and co opted from a precursor, then the gene encoding that precursor would need the new info to coincide wtih the morphological changes so it would arrive at the right time in the cell cycle.
Yes. That part isn't guesswork, but detective work.
Ahh, so they are not guessing? yet they dont know?
the poitn is, we can of course come to this conclusion, but only if you have already decided how it evolved. And of courese we must ask, is such a theory even plausible?
No, that's doesn't match what I've read. Who came to that conclusion?
Probably because you've mislearned the supposed evolutionary origins from creationist sources.
I mean the first ancetor of the organissms they were studying of course, sorry if i confused you. Oh, and i am not stupid enough to simply take a creationist source at face value without checking the "official story " before posting on it.
Which ones? I'll email them to you if you like.
I wish i had access to tonnes of these papers, thats where the real up to date work is being done, but i cant ask for the emails from you becuase otherwise i will only be even more hungry...but thanks alot for the offer!
A molecular biology text is chiefly concerned with molecular biology as it is *now*, not as it was 4 billion years ago. And Youtube? Needles and haystacks spring to mind.
And once again, you're looking for knowledge that we don't have. We don't know and perhaps can't know the details of what happened. All we can do is speculate, and examine whether those speculations are consistent with what we see now.
Well infact since we are unable to see the topo's of the past, AND it is postulated that topo existed in the first ancestor of archea and bacteria, AND topo has to perform a particular function with regards to DNA, then surely it wasnt much differetn in the past if it existed. When i say youtube, i mean real lectures from universities(is that bad?).
I don't know what you're thinking. We can look at something and see the reason for its existence in it's apparent purpose, its function. No origin theories required.
What so you dont need to explain how an ezyme came to be, but rather assume particular mechanissm explain it? oh and your right we can see the purpose of somethign, what was i actaully thinking? that was a mistake.
No, it doesn't work that way. That's a typical creationist caricature of evolution.
Actual evolution is about combinations and subtle changes in existing machinery or its environment, that sometimes results in new useful functions.
First off, i dont really worry whether or not my arguments are "creationsist" like, thats simply coincidence. And explaining to me the proposed processes of evolution does not get rid of the fact that it indeed did have to be there "on time", whether or not it was formed from a precursor, it still had to be in the right place on the dna on time, otherwose supercoiling woudl prevent access to base pairs.
its truly amazing what goes on just below our reality!
The idea that some amazing biological functions seen today sprang into existence fully formed is creationism. It is no part of evolution.
and i am not suggestign that, if i come across that way im sorry, becuase frankly i dont know how anything i see in the cell came about since so far almost everthign i have looked at is dependet on so many other factors as to boggle the mind.
Where did you hear it? In what context?
too many to adress, surely you in your reading have come across this slack phrasology that simply trivializes the entire origin of certain stuctures?
its pretty common actaully.
Like I said, the required machinery must have been there already, and performing some pre-existing function. Why is that miraculous?
Bingo! of course it must have been there(assuming this hypothetical time actaully occured the way we suspect)...but the fact that it had to be there already should indeed ring some alarm bells! becuase that means you have to explain(or guess based on what you belive or accept) how it was there "on time" for this event!! Now that is miracoulous if ever I've heard it.(infact life is full or miracles, and i dont mean that in a religous way)
mutations are stochastic and unawere of each other, logically, we should never expect this pre existing machinery you talk about to get the right chagnes "on time"..that is ludacris beyond words!!
Absolutely correct.
Once again i sound silly, your right of course there was a reason!! my problem is the how, as you can proberbly tell.
Then why are we having this discussion?
I think you do very much want to speculate on origins.
Isn't that what creationism is?
Not speculate on origin of life, but origin of adaptions at molecular and macro level, i dont claim to know anything about abiogenesis but i of courfse have my thoughts!
of course you should not confuse creationism with considering origin, that is simply a part of creationism, but anybody can think deeply on origins no matter their disposition.
Are you confusing coiling with supercoiling? Or are you only thinking of circular DNA?
Many full turns of non-circular DS DNA can be replicated before supercoiling becomes a problem, because the tension in the double helix can be relieved by twisting the whole molecule. It would have to be pretty long before that twisting results in a supercoiled tangle.
Im obviously not taking about those DNA that didnt need topo's,
but dont forget, you dont just releive tension by "twisting the whole molecuel"...you need helicases or analouge to do that(and initiating factors and ssbp's)..and that is a whole other mind numbing process. why should we expect a blidn process to innovate to this extent! or should we?
I will have many posts on molecular biology, im sure you'll be very interested, and i will try my best to thourougly think out my questions as to not sound like a creationist!
The relevance is that there would have been a reason for DNA manipulation before long DS DNA existed.
It seems like you are saying that becuase there was a reason, therefore it was there? there are many things taht would benefit from many other things, that does not mean they will ever get them.
Right, so the functions of DNA topoisomerase might have been performed less efficiently by other enzymes, at least for short DNA segments.
Can you see the potential for gradual change? As DNA maintenance machinery gradually becomes more efficient, it can gradually maintain longer and longer DNA strands.
There is no point at which development is halted unless several things appear at once.
