Talk:Hershey–Chase experiment

message: It was mentioned to us by our professor that we should discuss the recent findings on arsenic based life.  While these findings are controversial we do believe the applications to Hershey-Chase are significant and have therefore included the topic in this entry.   Jmn49114 (talk)  14:53, 30 March 2011 (UTC)
thread_title:  UMD BIOE120 

message: PEER REVIEW 
Team Nine
Hershey-Chase Experiment
 
 
For Team Nine’s peer review of Team One’s article, we read and edited the Wikipedia article on the Hershey-Chase experiment. Overall, Team One’s article on the Hershey-Chase experiment was very well written and detailed, with a few corrections to be made on organization and content.
First of all, while the opening sentence sums up what the Hershey-Chase experiments were, the last part of the sentence (“which had first been demonstrated in the 1944 Avery–MacLeod–McCarty experiment”) is probably not necessary information to be included; the opener should only include critical information about the experiment, so save this part for another sentence by itself. Also, the first section, which is just an overview of the article, can be shortened, as it is only supposed to provide a brief summary of the Hershey-Chase experiment; some of the detail is a bit redundant, as it is mentioned again under the heading “Methods and Results.’ The information provided in the very first section is too specific and detailed, which should be saved for the later sections and headings.
For the introduction and historical background section, the subheadings are a bit broad and underspecified. While the ‘previous assumptions’ section makes sense in relation to the overall heading of ‘intro and background,’ the sections ‘Need for clarification’ and ‘predictions’ do not say much about the background of the Hershey-Chase experiment. In other words, try to organize the information and details of ‘Need for clarification’ and ‘predictions’ into different headings under “Introduction and background,’ as they are a bit unclear. For example, since predictions are a part of making hypotheses change the ‘Predictions’ section to ‘Hypotheses’ and adjust the paragraph accordingly (which shouldn’t be by too much). In addition, the last sentence under ‘previous assumptions’ is wordy and confusing (“The multitude of functions that can be attributed to proteins was also known while DNA at the time had no known function, so it was sensible for scientists to believe that being genetic material and responsible for inheritance of traits could be just another function of proteins”); try to make the sentence shorter and more straightforward. Overall, the headings in this section are unclear and not very specific, but can be easily adjusted.
The “Methods and results’ section is very good and detailed. It includes all the necessary details about the experiment and does so in a clear and informative manner. This section could be expounded upon by moving some of the details from the very first opening section to this section, as mentioned before. The only other part of this section that could be changed is the ‘Limitations and opportunities for further research’ section; it does not directly relate to the experiment and results, and is instead more of the experiment’s impact on future DNA research. This could be made in to another section at the end of the article, where it ties in more to the implications and applications of the experiment.
Finally, for the “Applications’ section, the paragraphs on crime investigation and genealogy are a bit long and unrelated to the Hershey-Chase experiment itself; try to make these sections shorter and only discuss how the application related to the findings of the experiment. For example, for the crime investigation section, give a brief overview and then keep the last paragraph which relates directly to the experiment.
Overall, the article for the Hershey-Chase experiment is a very well written and in-depth article. The citations and pictures are all very good, and the edits for organization and content will help make the article flow more easily and read more like a scientific article.
Cashley1 (talk) 14:38, 12 April 2011 (UTC)
thread_title: Peer Review

message: ===Group 9 Review===
I do not think this sub heading should be changed because it does not simply say "background" but "historical background" and so in that we are implying that we are talking specifically about the historical events leading up to the experiment and not the background of the experiment itself.  — Preceding unsigned comment added by Richard.le12 (talk • contribs) 03:04, 23 April 2011 (UTC)
thread_title: RE: Peer Reviews

message: I do not think this sub heading should be changed because it does not simply say "background" but "historical background" and so in that we are implying that we are talking specifically about the historical events leading up to the experiment and not the background of the experiment itself.  — Preceding unsigned comment added by Richard.le12 (talk • contribs) 03:04, 23 April 2011 (UTC)
thread_title: Group 9 Review

message: I did not change the name of the "Establishing conceptual baselines" section because I think it accurately describes the goal of the section. Hershey and Chase lay out in their article the procedures they took just to be ABLE to preform their experiment. These preparations were not part of the experiment itself but were required in order to be able to achieve any significant conclusions from their results.  This process was a conceptually new idea based on observations from previous research by themselves and others and therefore merits its own section. Jmn49114 (talk) 15:28, 24 April 2011 (UTC)
thread_title: Group 3 Review

message: The citation for the use of X-ray crystallography in the determination of the structure of DNA is updated with a more recent article published by The American Institute of Physics in Mar 2003. This publication clearly indicates that Watson and Crick could not have proposed the double helix structure of DNA without accessing the experimental results obtained by Rosalind Franklin.Mengew79 (talk) 04:42, 25 April 2011 (UTC)
thread_title: Group 3 Review

message: Please note that a hypothesis is a statement about the phenomenon that answers a research question.  Usually it's broad in scope.  In this case, the hypotheses are "DNA is the genetic material (of T2 phage)" and "protein is the genetic material."  Statements about what should happen in a specific experiment if the hypothesis is correct are predictions, not hypotheses.  Predictions should be phrased as "If hypothesis A is true and experiment B is performed, then result C should occur."  They aren't phrased as "If you get result C, then hypothesis A must be true." For one thing, it's always possible that result A could be accommodated by some other hypothesis -- which is why we say that hypotheses are supported, not proven, when they make correct predictions. Agathman (talk) 20:16, 29 March 2011 (UTC)
thread_title:  Prediction vs hypothesis 

message: I see that this article has been nominated for review as a WP:Good article.  It's technically not required for GA status, but Wikipedia's Manual of Style specifies sentence case rather than title case for the capitalization of section headings.  (See WP:MSH for the full description.)  It's not part of the GA criteria, but it might be just as well to change it.  Good luck, WhatamIdoing (talk) 00:50, 3 April 2011 (UTC)
thread_title:  MSH 

message: Sadly, this article is full of inaccuracies. The Applications section, which I have hidden, describes techniques which are not at all related to the experiment. This has already been mentioned at the Peer Review. To say that most biologists believed proteins carried the heredity material in not true. Following the work from Avery's laboratory in 1944, and  by the time Hershey and Chase published their results in  1952, the belief that DNA was the genetic material was widespread. That's why Crick, Watson and others were so keen to determine the structure of DNA. Hershey and Chase were not convinced by their results and wrote, "Our experiments show clearly that a physical separation of the phage T2 into genetic and non-genetic parts is possible...The chemical identification of the genetic part must wait."  They published there results at the same time Watson and Crick published there DNA model in Nature, so timing was in Hershey and Chase's favour.  I think the article is overstating the importance of the experiment. It was not essential to our subsequent knowledge about DNA, it just provided a little more evidence of the role of DNA in biology—a role that was already widely accepted by the time of publication. Most textbooks only devote one or two pages to this subject, the claims currently made in this article are exaggerated and are not and cannot be supported by sources. Graham Colm (talk) 16:15, 24 April 2011 (UTC)
replies: text: I see that my edits that were made in attempt to restore the balance of the article have been reverted.  As a result the section on the historical background now contradicts itself. No page number is given for the Matthew Cobb; Morange, Michel (1998) citation, but this book does say this: "Early studies of molecular biology attributed the discovery of the genetic role of DNA to Hershey and Chase. It took protests from Avery's colleagues for his experiment to be restored to the pantheon of molecular biology. Even today molecular biology textbooks often put the two experiments on equal footing, ignoring the fact that they took place eight years apart". (My emphasis). This was written in 1998, modern textbooks do not perpetuate the myth, (See Lewin's Genes X, ISNB 9780763779924 pages 5 to 6, for example). The Lead section of the article gets the balance more or less right, but the first sentence of the historical background contravenes WP:NPOV and has unsupported attributions and weasel words. This is not how Good Articles are written.Graham Colm (talk) 18:22, 1 May 2011 (UTC)
replies: text: I have tried to simplify and correct the "Historical background" section so that it does not contradict itself.  I have stated simply that originally, proteins were thought to be genetic material, then the Avery-Macleod-McCarty experiment provided support for DNA as genetic material, which led to the Hershey-Chase experiment.  Homedog21 (talk) 21:25, 1 May 2011 (UTC)
replies: text: And the section is so much better. Simple statements of fact will really improve this article. We must try to avoid over-selling history. Graham Colm (talk) 21:48, 1 May 2011 (UTC)
thread_title:  Inaccuracies 

message: Depending on your language skills, it might be worth looking at versions of this article on other language Wikipedia pages. Anyhow, this image  is quite good. It does not seem to be available on the Commons, so if you decided to use it, it needs copying across. Graham Colm (talk) 08:25, 25 April 2011 (UTC)
replies: text: That is a good image. I am still in favor of using different colors for different radioactive isotopes (32P and 35S). If you can get access to the source file and edit it, that will be great. UM BIOE120 Instructor (talk) 13:41, 26 April 2011 (UTC)
replies: text: How about this?
Graham Colm (talk) 18:18, 26 April 2011 (UTC)
replies: text: Thanks, and good work.  I have incorporated this image into the "Experiments and conclusions" section.  It can be further edited (or potentially moved to another part of the article if it seems redundant) if necessary.   Homedog21 (talk) 02:49, 27 April 2011 (UTC)
thread_title: Image

message: Please be careful with comparisons to protein analysis, particularly in regard to DNA fingerprinting. This technique exploits variability in non-coding regions of DNA, i.e. DNA that is not used to direct protein synthesis, see Variable number tandem repeat). I have hidden some inaccurate statements. Please bear in mind that students all over the world will be reading this. Graham Colm (talk) 20:40, 29 April 2011 (UTC)
thread_title:  Comparisions with protein analysis 

message: I see my concerns over the inclusion of this section have been ignored and my edits reverted.  I remain completely unconvinced that this material belongs in the article. It has nothing to do with the experiment. It might, in time, be worthy of a new article, but it does not belong here. Readers who come to Wikipedia to read about the  Hershey-Chase experiment will not be interested in this tangential discussion. I shall delete the aforementioned section. Please do not restore this material without further discussion and consensus. Graham Colm (talk) 20:23, 21 May 2011 (UTC)
replies: text: Of course you are correct. The same information was added to Felisa Wolfe-Simon (—I reverted that addition because it appeared to be a list of items chosen by an editor to show defects in a paper, which is not appropriate in a BLP). Johnuniq (talk) 09:04, 22 May 2011 (UTC)
thread_title:  Arsenic-based life forms 

message: I just deleted the following:
However, once the DNA was inserted, it did not remain in the cytoplasm of the bacterial cell but was incorporated into the bacteria in some fashion (later determined to be inserted into bacterial DNA).  The infected bacterial cells were frozen to cause cell lysis and the release of most cellular material.  Upon examination, almost all of the phage’s labeled DNA was found to have been incorporated into the bacterial cells.
Bacteriophage T2 is virulent virus and is incapable of being inserted into the bacterial DNA, as is the case for lysogenic bacteriophage such as Bacteriophage lambda. In fact, the T-even bacteriophages degrade the host chromosome as part of their life cycle. The DNA from the infecting phage is used as the template strands for the semi-conservative DNA replication for production of progeny phage. The nature of the DNA replication systems of T-even phage means that the parental DNA will be fragmented among progeny molecules by recombination. Interestingly, the experiment to show phosphate in the progeny is cited in the text with no data shown. They were not the first to show DNA phosphate transfer between generations - they cite earlier work on page 52. --JimHu (talk) 23:41, 3 February 2014 (UTC)
thread_title:  Injected DNA was not integrated into the bacterial DNA 

message: The picture of Martha Chase is in fact a picture of Charlotte Auerbach : https://en.wikipedia.org/wiki/Charlotte_Auerbach 192.41.114.225 (talk) 11:22, 9 October 2023 (UTC)
thread_title:  wrong picture for Martha Chase