Talk:C-value

Discussion merged in from old C-value enigma page
The article on non-coding DNA notes that there is an amoeba with 200 times as much DNA as a human, and that genome size does not necessarily correlate with organism complexity. When I saw this, I recalled a shirt I saw when I was in college: "Everything I learned in life, I learned by killing smart people and eating their brains".

My question is: Does the genome size correlate with genome age? -Joe
 * Nope. Evolver 00:35, 11 October 2005 (UTC)

OK. I have another question then. How many genomes are there and how many are in databases? -Joe
 * How many genomes? As many as there are species (maybe 10-100 million); or, if you look at it another way, as many as there are individual organisms; or, yet another way, as many as there are cells making up those organisms.  What databases do you mean? Genome sequences?  Genome sizes?  Chromosome numbers?  Evolver 20:16, 12 October 2005 (UTC)

Change title to "genome size paradox"
Of the (small) fraction of scientist who know the term C-value paradox/enigma none could explain to me the meaning of C-value? The term obscures the meaning more than it helps to spread the idea. Therefore, I would like to see the title of this wikipedia entry changed to genome size paradox. This incorporates the crux of this enigma and is not just a relic. I just put this here as a suggestion to the more specialised scientists working on this entry. - Jasu, Dec 2005


 * Sorry, but no one uses the term "genome size paradox", either in common language or technical publication. So, this article should definitely stay "C-value enigma".  There is a separate entry for C-value in wikipedia that you can consult. The short definition is that it is the amount of DNA in a haploid nucleus, which is essentially Constant within species.  Anyone who works on genomes will be familiar with the term "C-value paradox", so this is not an obscure concept, even if this does constitute a "small fraction of scientists" (I suspect just about any specialized jargon will be known only to a "small fraction" of the overall scientific community!) 209.29.83.124 14:27, 31 December 2005 (UTC)


 * Correct but nobody here uses the term "C-value enigma" either. We use "C-value paradox" (or rather, in german, C-value paradoxon, but we also "translate" this into english, and the english literature we used consistently refers to the "C-value paradox".) To me it sounds as if someone tried to write an article in favour of the word C-value enigma, when everything else contradicts that choice. 84.112.136.52 (talk) 18:30, 9 October 2013 (UTC)

Is this a proper thing to say (in C-value paradox as well):
 * Non-coding DNA has many functions yet to be discovered.

Is it possible to know it has undiscovered functions? That may be postulated, but certainly not proven IMO.

Verbage sounds contradictory
In one paragraph, the wording sounds contradictory to me (who admittedly knows almost nothing about the topic) "The discovery of non-coding DNA in the early 1970s resolved the C-value paradox...Though now it is known that only a fragment of the genome consists of genes, the paradox remains unsolved."

Perhaps this article needs tagging with 'needs expert input' or whatever that tag is, to clear up the verbage on the C-value enigma (or paradox, or whatever it's called.)

Yeah, what the hell? —Preceding unsigned comment added by 96.233.45.165 (talk) 22:03, 26 February 2009 (UTC)

The paradox is unsolved. The revelation that much of the DNA was noncoding did not "solve" the problem. It still does not explain why there is so much variation in c-values. There appears to be no correlation in c-value and complexity, or taxa, etc. I am a genetics and evolution student, and they still teach this.129.59.47.19 (talk) 14:32, 9 April 2009 (UTC)

In addition, this is historically incorrect. King and Jukes in 1969 - before the term c-value paradox had been coined and then apparently solved - stated: "Perhaps the most compelling argument for the existence of superfluous DNA is the wide range in the DNA content of vertebrate cells (40, 41). The average mammalian cell contains more than twice the DNA of the chicken cell and almost four times that of the cell of the gar pike. The cell of the bullfrog contains twice as much DNA as that of the toad, and two and a half times as much as that of a man, while the cell of a lungfish has a DNA content 17 times that of the human cell and almost 60 times that of the pike cell. Can it be that these wide divergences in DNA content reflect wide divergences in the number of functional genes? This hardly seems likely." (p 794). They also stated: "it is probable that not much more than 1 percent of mammalian DNA codes for proteins." 156.62.3.21 (talk) 00:54, 11 June 2014 (UTC)

Merge
The old C-value enigma page depended so much on the C-value page and vice versa and they were both short. I have therefore merged them together by just expanding the variation between species section. T.Shafee(Evo&#65120;Evo)talk 01:44, 19 April 2015 (UTC)

bp Units
Leegrc: Though all of the articles I read use kb and Mb for thousands and millions of base pairs (and it's the standard listed in Wikipedia's Base_pair), I know that some online dictionaries do use kbp and Mbp instead - and I won't quibble further. ATcompGC (talk) 18:37, 21 April 2015 (UTC)


 * In many cases, it does not matter whether one is counting bases or base pairs, e.g., the length of the haploid human genome is 3 billion bases or 3 billion base pairs; for describing length, it does not matter which one one uses. However, in this case we are weighing the DNA, and double-stranded DNA will weigh twice as much as single-stranded DNA of the same length.  I made the change to the less ambiguous notation (Mbp instead of Mb), so as to make that distinction as clear as possible.  Leegrc (talk) 20:04, 21 April 2015 (UTC)


 * Fair enough. When you're doing distance, the distinction between bases and base pairs doesn't matter, but when you're doing weight, it does. They certainly are base pairs per picogram.ATcompGC (talk) 21:14, 21 April 2015 (UTC) — Preceding signed comment restored by Leegrc (talk) 14:25, 22 April 2015 (UTC)

clarification needed
This article has some omissions that need to be filled in. It spends a disproportionate amount of time on semantics (paradox vs enigma!).


 * First, explain why c-values are used instead of basepairs for measuring the quantity of DNA.
 * Second, the calculations need to be clearer. If c-value is in picograms, then show better where they come from. Why is the mass of the 4 nucleotides in a table when it's not used anywhere, instead some density number pops up in the next table.
 * If c-value doesn't relate to cytosine (instead C means constant), then make clear why CG pairs are being used.
 * Finally, we need other examples of C-values. If humans have a c-value of 3, then some other animals should have c-values of 3000 or 0.003 (given the opening statement that C-values in animals vary by 3 orders of magnitude). Show this. Show us some other c-values, and provide references to published data to indicate that the c-values stated are correct. — Preceding unsigned comment added by Lehasa (talk • contribs) 07:24, 27 January 2016 (UTC)

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Rewrite of "Variation among species" section needed.
This section is poorly consolidated as a result of the merges and edits over the years. The "paradox vs enigma" subject is addressed three times in succession by differrent editors. This is obviously redundant, and puts too much emphasis on a minor terminology dispute in comparison to the actual subject of C-value.

In addition, the phrase "among species" is problematic. Since one meaning of "among" is "within a certain group", "variation among species" can be easily misunderstood as "variation within a species". I suggest using "variation between species" to emphasize that different species are being compared.

174.198.239.100 (talk) 06:56, 26 November 2020 (UTC)

Further standards
Greilhuber is mentioned as a source where further standardization's were made particularly with regard to polyploidic organisms,should these be given in the article? Chris folowed by a random set of numbers (talk) 06:38, 4 December 2023 (UTC)