Talk:DNA/Archive 9

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Intro passage fact by fact

First paragraph:

  1. DNA should not be defined as "the primary chemical component of chromosomes". Prokaryotes don't have chromosomes and they make up two of the three major lineages of life. Bensaccount 15:35, 7 Mar 2004 (UTC)
  2. DNA should not be defined as "the material from which genes are made" since DNA also is the material from which other things (intron etc.) are made. Bensaccount 15:39, 7 Mar 2004 (UTC)
  3. Defining DNA as "the molecule of heredity" is only half right. DNA also has other functions which should be listed (DNA determines the structure and functions of the cell). Saying that DNA is the "molecule of heredity, structure and function of the cell" sounds bad. (Also I believe it has already been said that DNA is a macromolecule.) Bensaccount 15:50, 7 Mar 2004 (UTC)

Above are the three facts from the first paragraph, all incorrect. The problem appears to be that this paragraph is too specific. It constrains the actual properties of DNA. What is needed is a more general, less constraining introduction. Bensaccount 15:54, 7 Mar 2004 (UTC)

If you think any of the three sentences are actually correct, you have to prove me wrong (and I dont want to try and make sense of an essay so keep it breif).

Heres my suggestion for the first paragraph:

Deoxyribonucleic acid (abbreviated DNA) is a macromolecule that encodes heritable biological information of a cell. It determines the structure and functions of the cell.

This is only two sentences and it doesnt constrain the meaning of DNA and it actually includes more information than the previous paragraph. Bensaccount 16:04, 7 Mar 2004 (UTC)

Second paragraph:

  1. "In bacteria and other simple or prokaryotic cell organisms, DNA is distributed more or less throughout the cell. In the complex or eukaryotic cells that make up plants, animals and in other multi-celled organisms, most of the DNA resides in the cell nucleus. ". Firstly, in prokaryotes ("prokaryotic cell organisms") DNA is found in the nucleoid region. Seconly prokaryotic and eukaryotic DNA demand their own subsections and should not be part of the intro.
  2. "The energy-generating organelles known as chloroplasts and mitochondria also carry DNA, as do many viruses. ". Firstly chloroplasts and mitochondria are in cells so this is already covered (put it in subtopics). Secondly, there is some info here that should be included so:

Deoxyribonucleic acid (abbreviated DNA) is a macromolecule that encodes heritable biological information of a cell. It determines the structure and functions of the cell. DNA can also be found in viruses.

If DNA can be found outside of cells in other forms, list them after virsuses.

All that information has been compacted into two sentences. I want a comment mainly from 168. If anyone else is likely to revert this sentence if it is used I want their comment as well. Bensaccount 16:07, 7 Mar 2004 (UTC)

[P0M:] The formulation looks pretty good to me, but following the links to "biological" and "information" would not be helpful to novice readers. Probably it would be better either to just remove those links and supply an explanation of what you mean by "biological information" later in the article, or else put the explanation in a separate linked article called "biological information." I seem to recall discussions on this page about what "information" "really means," so (even that terms makes sense to me) you may find that it is controversial. P0M 17:24, 7 Mar 2004 (UTC)

Deoxyribonucleic acid (abbreviated DNA) is a macromolecule that encodes the structure and functions of a cell. This biological information is heritable, hence the common phrase molecule of heredity. DNA can also be found in viruses.

Ok by getting rid of some redundancy I made room to include "molecule of heredity" which is more a stylistic point but doesn't do any harm as long as everything else is clear. Bensaccount 18:04, 7 Mar 2004

[P0M:] "Molecule of heredity" is not a clear formulation. I think I can figure out what those words are intended to convey, but our goal should always be to say things cogently in the first place. IMHO, some of the bad edits in the history of this page have come as a result of a certain individual harvesting all manner of inexact formulations from mass media sources and insisting that they be used because they had previously been used. See Slrubenstein's comments below.

(UTC)

I hate to step into the middle of an edit-war, as I have been in some myself in the past and know not only how heated passions may get, but how hard it can be to deal with new substantive issues. I genuinely hope that the involved parties can resolve their current dispute. I have looked over the recent history only cursorily but it appears to me primarily to be a matter of style (if I am misunderstanding someone's point, I apologize -- I am NOT attempting to get involved in this particular issue. At all.) I am concerned with one phrase in the intro, and my concern is for substnative reasons. Given the current state of affiars I will not make any changes to the article but I really would appreciate some reasoned discussion of this issue and perhaps soon we can make an acceptable change. I take issue with this: "because they propagate their traits by doing so." There are many people today who are not well-trained in the biological sciences who believe that genes or DNA determine the nature of the organism, and I fear that those people who read this phrase will have their mistaken belief reaffirmed. Perhaps the author of this phrase, in writing "propogate thier traits" simply meant "traits of the DNA" i.e., specific nucleotide sequences. However, I think most people will read this and think "traits of the organism." This is a mistake. Yes, DNA plays a major role in the reproduction of the organism and thus in the traits of the organism. Emphasis on "role." I object to the languate "propegate their traits" because I believe too many will infer that DNA does this by itself, and completely. In fact, DNA cannot propegate traits by itself, it require many other chemical and biochemical processes in addition (so we could say that they play a role in propegating traits?). Moreover, other things besides DNA affect the traits of the organism -- environmental and developmental processes both within the cell during the process of replication; within a zygote and embryo, and later in the life of an organism. So I think the language here must be more specific and more constrained. I beg others like 168 and Mav and Lexor who have been more active on this page to suggest alternatives and maybe we can come up with something we can all agree to. Slrubenstein

I second your request that things "be more specific and more constrained. P0M 18:26, 7 Mar 2004 (UTC)

Good point (though long winded). Heres the current proposition (see above):

Deoxyribonucleic acid (abbreviated DNA) is a macromolecule that encodes the structure and functions of a cell. This biological information is heritable, hence the common phrase molecule of heredity. DNA can also be found in viruses.

I think what you are referring to is the central dogma of molecular biology. It should definately be included. I also took out the heredity stuff which the more I think about the more unscientific it seems. If you want to know about heredity, make it a subtopic or better yet a whole different article, because it is much more complicated than saying that DNA is a molecule of heredity.

Deoxyribonucleic acid (abbreviated DNA) is a macromolecule that encodes the structure and functions of a cell. It is the first component in the central dogma of molecular biology (DNA → RNA → protein). DNA can also be found in other entities such as viruses. Bensaccount 18:20, 7 Mar 2004 (UTC)

[P0M:] The above formulation mixes universes of discourse. Is DNA a molecule or is it a tenent is some dogma?

It is both (and its not just some dogma its the central dogma to molecular biology). Bensaccount 18:48, 7 Mar 2004 (UTC)