Talk:Chargaff's rules

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Credit for Chargaff

Yes, well i believe that Chargaff was a huge contributor to finding the shape of DNA and i believe he should recieve some credit for his works. Without him Watson and Crick would have to start from scratch and would not have known where to begin. They were smart men but they used Chargaff's rules and ideas to do their research. I believe Chargaff should get a Nobel Prize for his work because it wasnt just Crick and Watson who discovered the shape. he was the base of that whole project. Well thank you and please just think about it.

LOVE ALWAYS Rachel A. — Preceding unsigned comment added by 72.72.97.102 (talk • contribs) 01:20, 24 March 2007 (UTC)[reply]

Then what of all the discoveries and their discoverers before Chargaff, all of which and of whom made it possible for Chargaff to make his discoveries? Building upon other people's work is the way progress gets made; not everyone in the chain of antecedents can be legitimately credited with work built upon them. Fact is that Chargaff didn't figure out the key to how DNA stores heritable information, whereas the Nobel conferred to Wilkins, Watson and Crick was for precisely that feat. — Preceding unsigned comment added by 24.223.130.60 (talk) 19:41, 1 February 2013 (UTC)[reply]

Experiment Results Citation

I have a citation for the experimental results, but don't know how to post them. Here's the source, in MLA format.

Mallery, Charles. "Chargaff's Rules Of Base Pairing." University Of Miami Dept. of Biology. 04 Sep 1997. University Of Miami. 13 Apr 2008 <http://fig.cox.miami.edu/~cmallery/150/gene/chargaff.htm>.

If someone better with computers could edit it in, it would be appreciated. —Preceding unsigned comment added by 69.158.145.237 (talk) 18:46, 13 April 2008 (UTC)[reply]

Errors in AT/GC-Table

The numbers of the AT/GC-Table cannot be true: Whereas the first six examples follow the Chargaff-rule, the other seem to be mixed up. Maybe one can correct this. 217.7.215.116 (talk) 13:53, 17 March 2009 (UTC)[reply]

Thanks for noticing this. I fixed it. The order of the columns was out of order with respect to the header. --Thorwald (talk) 00:53, 18 March 2009 (UTC)[reply]

Is there any reason the organisms in the table are not in some kind of taxonomic order? It seems like it would be more meaningful if related organisms were grouped. Eperotao (talk) 00:12, 7 November 2014 (UTC)[reply]

Suggest the following order:

φX174
E.coli
Maize
Wheat
Yeast
Grasshopper
Octopus
Sea Urchin
Chicken
Rat
Human

Eperotao (talk) 00:17, 7 November 2014 (UTC)[reply]

Two sentences

"oligonucleotide is present in equal numbers to its reverse complementary nucleotide" I don't understand. Maybe it should be: "oligonucleotide is present in equal numbers to its reverse complementary nucleotide sequence" or "oligonucleotide is present in equal numbers to its reverse complementary oligonucleotide" ?

"listing the base composition of DNA from various organisms a support both of Chargraff's rules". Hier I don't understand "a support". Syntax seems not to work.

Thanks for clarification.

217.82.189.33 (talk) 18:07, 25 March 2009 (UTC) MarcoP Berlin[reply]

Deamination

The current text says "In single stranded DNA, cytosine spontaneously slowly deaminates to adenosine (a C to A transversion)." I know about C-to-T deanimation (which is a transition, not a transversion), but how can a pyrimidine deaminate to a purine? Even if the text is correct, I think a little explanation would be helpful. --Ralf Muschall (talk) 16:52, 9 December 2011 (UTC)[reply]

Still nobody wanting to take this? ;-) I might do it myself, but (not being a biologist) this might be replacing an obvious, easy-to-spot error with a more subtle one that is still wrong and stays for eternity. --Ralf Muschall (talk) 12:15, 30 September 2012 (UTC)[reply]

I just noticed this as well. C can most definitely not deaminate to A; as you say it deaminates to T. I presume the text is trying to say that upon C-T conversion, the strand is copied to yield an A. — Preceding unsigned comment added by 131.111.116.31 (talk) 10:38, 19 September 2014 (UTC)[reply]

cytosine to thymine, not adenine

Cytosine deaminates to form uracil, not adenine. Uracil base pairs like thymine. Replication results in an insertion of A opposite the the U (if the U isn't repaired in time). Replication of this new, mutated strand will result in the insertion of a complementary T. So, deamination of C leads to a "C to T" change in the sequence of the DNA. — Preceding unsigned comment added by 208.91.4.78 (talk) 23:09, 3 May 2015 (UTC)[reply]

Usage of '~' and 'oligonucleotides' unclear - add brief definitions; Inconsistent Explanation for Second Rule

Assume the article is being read by a non-biologist and briefly explain the jargon to enhance clarity. Also multiple second rules are given, apparently inconsistent with each other - which is right?

1) The formulae and %A ~ %T and %G ~ %C need a textual explanation - what is the tilde (~) supposed to represent? Approximately equal? Doesn't that immediately follow from the first rule? (If the %'s are the same, then the counts should also be the same.)

2) A sentence on what 'oligonucleotides' means in the present article would also be helpful - here it looks like it means a short contiguous sequence of DNA on a larger DNA strand, as opposed to a standalone short DNA sequence (Wikipedia's definition). An explicit definition for oligonucleotides would help by eliminating the need for guesswork.

3) Two different second rules are stated in the article. Which is right? The first definition given is: "The second rule holds that both %A ~ %T and %G ~ %C are valid for each of the two DNA strands.[3] This describes only a global feature of the base composition in a single DNA strand.[4]" It is clear that this definition is focused on what happens on a single strand (irrespective of my confusion over what '~' means.)

The second definition of the second rule is in the next sentence under the Research heading: "The second of Chargaff's rules (or "Chargaff's second parity rule") is that the composition of DNA varies from one species to another; in particular in the relative amounts of A, G, T, and C bases." It is clear this definition is focused on a comparison between species.

It would seem the definition can't be both of these. More likely what was intended is that the definition is one of these (but which?), and the implications of that definition are the other statement. — Preceding unsigned comment added by 74.51.155.210 (talk • contribs) 16:39, 14 October 2017 (UTC)[reply]

A% or %A, which is expected?

Two notations exist in the description. Isn't it good to use just one of them? Timeofglacier (talk) 07:58, 19 June 2023 (UTC)[reply]