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In vitro or automated DNA Synthesis

Perhaps a section about how DNA is synthesized in the laboratory?

The Picture

Shouldn't "ozaki fragments" in the picture (png) be "okazaki fragments"?

rolling circle rep include also

Easy to break, even easier to fix?

For those of you who know a little more about the licencing factors, how about an explanation of why gene shearing is an accepted technology - do we really know what control mechanisms are involved here ? Or is the inherent capacity of the cell to allow for our meddling, increasingly a source of wonder?

More info?

I looked at this page while doing some homework for my high school biotechnology class and found that it was missing a lot of key information. For example:

-DNA-B first marks the initiation site for Rep (aka Helicase) to begin "cutting" the DNA -DNA Gyrase relaxes the supercoiling so that the section of DNA that needs to be replicated is stretched out -topoisomorase (not sure on spelling) breaks covelant bonds (not sure why, I believe so that Rep has a place to start cutting the strands)

Also, the DNA polymerase referred to in the picture is DNA Polymerase III, and DNA polymerase I is involved in removing the segments between the Okazaki fragments (because they were created by RNA Primase and use RNA nucleotides).

I would just edit the article, but this is from notes I took from my teachers lecture and I'm note sure whether or not to submit...

Topoisomerase and DNA Gyrase are the same enzyme, it just has action in both supercoiling and uncoiling, the fluoroquinolone class of drugs work here actually. Additionally the picture is an extremely simplified representation of DNA synthesis, rather than edit it I would look for a more complete picture that has Pols 1-3 and a description of what they do and in which direction they do it. Most Pols have action in both the 3-5 and 5-3 directions. Pol 1 removes the RNA primers and repairs the region with the last few bases between fragments, ligase is still required for the final 'stitch' between the fragments.

Etherealmuse 8:05, 17 Feb 2005 (UTC)

This page also fails to address the obvious question of how the enzymes know how to complete these complex tasks. As it is, we appear to have an obscurium per obscurius, whereby the propensities of celled creatures are explained by a code, but the actions of enzymes remains a mystery. Are enzymes also driven by a code or are they automatically tripped, like thermostats? It is implied by the terminology used if nothing else that decisions are being made by these enzymes. How do enzymes make decisions? If there is a Wiki article that begins to explain this, there should be a link. Neither the enzyme nor the enzyme kinetics article does so.81.164.252.74 00:57, 6 August 2006 (UTC)

Quick Fix

The information about the speed of replication in humans had an error that I cleaned up quickly. It said something to the extent that the an average human chromosome had 6 billion base pairs. This is wrong, the entirety of the human genome has ~6 billion base pairs, which are themselves arranged in 46 linear chromosomes. Average chromosome length is not a particularly good reference as it varries considerably (spanning several orders of magnitude). I cleaned it up to reflect this fact.

-Mr. Knuffke

Umm. They don't even span a single order of magnitude - the smallest (21) is 47 megabases and the largest (1) is 245 megabases. Graft 17:30, 8 August 2006 (UTC)

Why can DNA only be replicated in the 5 - 3 direction?

If anyone knows it would probably be worth putting in the article.

DNA replication proceed in the 5' to 3' direction because the substrates for DNA replication, like RNA polymerization, are 5' nucleoside triphosphates. In DNA replication the 2' deoxynucleoside triphosphates elongate nacent chains in a template-directed fashon by cleavage of pyrophosphate (the terminal two of three phosphate groups) and transesterification of the remaining phosphate to the free 3- hydroxyl group of the growing chain. This increases the chain length by one nucleoside, generates pyrophosphate, and reconstitutes another 3' hydroxly group for continued chain elongation.

Also: The asymmetery of the promoter sequence

Prokaryotes and Eukaryotes

In my opinion there should be to separate articles for DNA replication in prokaryotes and DNA replication in eukaryotes. At least it should be made clear if prokaryotic DNA replication or eukaryotic is described. I think I know these two processes quite well, but people who read this to learn about DNA transcription will be unnecessarily confused by unclear parts in this article.

Additionally I think the different eukaryotic polymerases should be mentioned. They are very essential! I suggest copying some of the information from the wikipedia article DNA polymerases.

--Happy Puppy 01:38, 2 August 2006 (UTC)

Too Complicated!

I'm a Year 12 biology student, and I had heaps of trouble understanding much of this page. --218.215.130.252 10:36, 20 August 2006 (UTC)

New link to pic and agreement

I am suggesting that we add a picture found on the main DNA page, but not found here. The pic to be added to theis page is found here: http://en.wikipedia.org/Image:Dna-split.png

I do not know how to add pics, so please can either someone tell me, or post a link to where i can learn how to myself on my talk page.

Just a quick note - I agree with 218.215.130.252, It is a bit complicated, so a SIMPLE summary section would be nice. I am doing DNA as part of my GCSEs in the UK.

Thanks

Stwalkerster 21:23, 16 September 2006 (UTC)

Expert

I may have failed the DNA unit in Biology, but when I was working on an assignment I got confused. Is this DNA replication or protein synthesis?

--Falconus|Talk 00:43, 10 October 2006 (UTC)

It is DNA Replication, although this can sometimes be called "DNA Synthesis" as in the new daughter strands are being synthesised. Protein synthesis involves transcription and translation (I can never remember the diff) and the various RNAs. (t-,m- and r-?) Although I do agree that it needs a good looking over.GiollaUidir 13:13, 18 October 2006 (UTC)

Also, while most of the information does appear to be correct there are no refs given anywhere in the text!GiollaUidir 13:15, 18 October 2006 (UTC)

Bidirectionality

I was reading the DNA replication, and unable to find information pertaining DNA replication's bidirectionality. I think it is very important to have a section to explain the DNA's bidirectionality replication of a chromosome, as well as a contradictary example of unidirectionality. —The preceding unsigned comment was added by Wolingfeng (talk • contribs) 22:25, 6 December 2006 (UTC).

Feedback

I saw that people were saying how unclear the article was, so I made some changes (but am not done yet). Could someone, preferably someone who is not a molecular biologist or a biochemist :), read few of my changes, so I know if it is understandable to a more general public?

I will make further changes/addition in upcoming days.

also, if someone has more/better ideas, change stuff around!

thanks, Svetlana Miljkovic 13:12, 20 December 2006 (UTC)

DNA replication video

http://www.wehi.edu.au/education/wehi-tv/dna/replication.html This little animation from different angles should be helpful for those interested how DNA replication works. --Artman40 10:38, 30 December 2006 (UTC)