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ton ton
wrote...
Posts: 102
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11 years ago
This is the only thing that I can't figure out. If evolution wasn't guided by some intelligent creator, then how did DNA, it's corresponding enzymes and ribosomes arise spontaneously over time? Is there any naturalistic, progressive explanation on how this may have happened? At least in theory? How the DNA code and so forth developed?
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wrote...
11 years ago
You're arguing apples and oranges.  Abiogenesis deals with the creation of life from nothing.  Evolution merely states that organisms have changed and adapted in the time that it's been here.
wrote...
11 years ago
>>>>How did DNA, it's corresponding Enzymes and Ribosomes arise by evolution?>>>>This is the only thing that I can't figure out.

Really? Only this but all the rest of biology is clear to you? Because if you really have figured out all the different branches of biology and how biological systems from macromolecules to ecosystems then you would be aware of the power of selection on variations in populations.  

>>>>If evolution wasn't guided by some intelligent creator, then how did DNA, it's corresponding enzymes and ribosomes arise spontaneously over time?

1. You are presented with a puzzle/question/new phenomenon.
2. You do not understand or can?t figure out this puzzle/question/phenomenon.
3. Invoke magic as the answer.
How is this answer different from the invocation of magical powers by innumerable primitive tribes over millennia of stone-age existence?
Is this really the thought process of a rational, enlightened person in the 21st century? ?I don?t understand so it must be magic.?

>>>>Is there any naturalistic, progressive explanation on how this may have happened?

Yes. The previous poster has provided you with links to only a minuscule slice of the research on this subject.

>>>>At least in theory?

In science, a theory is not a guess. It is not a supposition. It is not a notion that could be possibly true.  A theory has withstood rigorous experimental testing before being acknowledged as the best model to explain a natural phenomenon.

>>>>How the DNA code and so forth developed?

The genetic code is one of the strongest pieces of evidence that supports the Theory of Evolution by Natural Selection. How it evolved (and still is evolving) is a fascinating subject that we are creating a model for.

There are those who see a problem and instead of invoking magic, they propose a natural mechanism and continue to test and search for a possible answer. The more effective and useful method of problem solving should be obvious.
wrote...
11 years ago
do you have a doctorate in genetics or biochemistry?

if not, you're not likely to understand much of it, at least in detail... no offense intended
wrote...
11 years ago
A lot of people are ridiculing you for suggesting that you could be expected to just "figure out" major scientific discoveries on your own.  I feel that this ridicule is unwarranted and childish.  A lot of people understandably think they can figure anything out on their own at first, and if they can't, they ask questions, as you just did.  I see nothing wrong with that, and neither would a biologist if you decided to chat with one about it.

So here's a brief, non-technical overview of the answer to your question (what a concept).  Disclaimer: I am not a biologist, and the following is gleaned from a casual study of the subject from educational information available to non-experts.  It is entirely possible that some of it is mistaken and I'm sure someone will correct me if it is.

First of all, you have to understand that DNA originally evolved from RNA.  Many microorganisms still exist today that have not yet discovered DNA, and do everything with 100% pure RNA.

Second, note that much of the core cellular machinery (by which I mean the things that are absolutely crucial no matter what, like ribosomes) seem to be made of either pure RNA or a mixture of RNA and proteins, whereas the other stuff in our cells are mostly made of proteins.  Since the core stuff is the stuff that changes the least with time, this might suggest that RNA actually came before proteins!  RNA by itself turns out to be able to form all kinds of chemical machines and gadgets, just like proteins do, without every needing any translation into proteins (the job of ribosomes, as I'm sure you know).

Third, realize that RNA could potentially have formed from another nucleic acid such as PNA, GNA, or TNA, and been so much more effective than these (for various reasons) that it beat out all of those and eventually left no trace of them, so now all we ever see are RNA and the slightly-cooler DNA.

Fourth, note that it isn't hard to replicate some kinds of nucleic acid.  In the right environment, it practically does it itself.  Occasional mutations naturally occur.  So maybe all you need is the existence of nucleic acid bases in order to start to evolve self-replicating chains of (something)NA, which then soon start to develop into shapes that naturally twist into little machines to promote and protect themselves better, which soon becomes RNA, etc.

Fifth, some of these nucleic acids may have arisen naturally in the chemistry of certain regions on the early Earth.  And that would possibly explain everything.

What I just described is called the "RNA World Hypothesis", and I think it's just one among many of the available hypotheses about how things might have all started.  It's very hard to know which idea is right because all the early organic compounds probably got gobbled up without a trace, so there isn't much we can go on, unfortunately.  But that doesn't mean that none of them is likely to be correct, just that it's hard for us to say which.
wrote...
11 years ago
Nucleases are enzymes that cut DNA strands by catalyzing the hydrolysis of the phosphodiester bonds. Nucleases that hydrolyse nucleotides from the ends of DNA strands are called exonucleases, while endonucleases cut within strands. The most frequently used nucleases in molecular biology are the restriction endonucleases, which cut DNA at specific sequences. For instance, the EcoRV enzyme shown to the left recognizes the 6-base sequence 5′-GATATC-3′ and makes a cut at the vertical line. In nature, these enzymes protect bacteria against phage infection by digesting the phage DNA when it enters the bacterial cell, acting as part of the restriction modification system. In technology, these sequence-specific nucleases are used in molecular cloning and DNA fingerprinting.

Enzymes called DNA  ligases can rejoin cut or broken DNA strands.Ligases are particularly important in lagging strand DNA replication, as they join together the short segments of DNA produced at the replication fork into a complete copy of the DNA template. They are also used in DNA repair and genetic recombination
wrote...
Staff Member
11 years ago
do you have a doctorate in genetics or biochemistry?

if not, you're not likely to understand much of it, at least in detail... no offense intended

That's not very nice, the whole purpose is to shed your knowledge - not keep it burning within Wink Face
- Master of Science in Biology
- Bachelor of Science
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