Editing Hershey–Chase experiment (section)

==Discussion==

===Confirmation===
{{further|DNA|DNA#History of DNA research}}

Hershey and Chase concluded that protein was not likely to be the hereditary genetic material.  However, they did not make any conclusions regarding the specific function of DNA as hereditary material, and only said that it must have some undefined role.<ref name=Hershey /><ref name="OConnor">{{cite news | last=O'Connor| first=Clare | title=Isolating hereditary material: Frederick Griffith, Oswald Avery, Alfred Hershey, and Martha Chase | year=2008 | url=http://www.nature.com/scitable/topicpage/isolating-hereditary-material-frederick-griffith-oswald-avery-336 | work=[[Nature Publishing Group|Scitable by Nature Education]] | access-date=20 March 2011}}</ref>

Confirmation and clarity came a year later in 1953, when [[James D. Watson]] and [[Francis Crick]] correctly hypothesized, in their journal article "[[Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid]]", the [[double helix]] structure of DNA, and suggested the [[DNA replication|copying mechanism]] by which DNA functions as hereditary material. Furthermore, Watson and Crick suggested that DNA, the genetic material, is responsible for the synthesis of the thousands of proteins found in cells. They had made this proposal based on the structural similarity that exists between the two macromolecules: both protein and DNA are linear sequences of monomers (amino acids and nucleotides, respectively).<ref name="pmid16578429">{{cite journal |vauthors=Pauling L, Corey RB| title = A Proposed Structure for the Nucleic Acids | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 39 | issue = 2 | pages = 84–97 |date=February 1953 | pmid = 16578429 | pmc = 1063734 | doi = 10.1073/pnas.39.2.84| bibcode = 1953PNAS...39...84P | doi-access = free }}</ref>

===Other experiments===
<!--this may be more detailed than appropriate for this article-->
Once the Hershey–Chase experiment was published, the scientific community generally acknowledged that DNA was the genetic code material. This discovery led to a more detailed investigation of DNA to determine its composition as well as its 3D structure. Using [[X-ray crystallography]], the structure of DNA was discovered by James Watson and Francis Crick with the help of previously documented experimental evidence by [[Maurice Wilkins]] and [[Rosalind Franklin]].<ref name="Physics Today-2003">
{{cite web
 | url = http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHTOAD000056000003000042000001&idtype=cvips&bypassSSO=1
| title = L.O. Rosalind Franklin and the Double Helix. Physics Today, March 2003
 | access-date = 2011-04-06
 | publisher = Physics Today
}}</ref>
Knowledge of the structure of DNA led scientists to examine the nature of genetic coding and, in turn, understand the process of protein synthesis. [[George Gamow]] proposed that the [[genetic code]] was composed of sequences of three DNA base pairs known as triplets or [[codons]] which represent one of the twenty amino acids.<ref name="isbn0-465-09138-5">{{cite book | author = Crick, Francis | title = What mad pursuit: a personal view of scientific discovery | chapter-url = https://archive.org/details/whatmadpursuit00fran | chapter-url-access = registration | publisher = Basic Books | location = New York | year = 1988 | pages = [https://archive.org/details/whatmadpursuit00fran/page/89 89–101] | isbn = 978-0-465-09138-6 | chapter = Chapter 8: The genetic code }}</ref> Genetic coding helped researchers to understand the mechanism of [[gene expression]], the process by which information from a gene is used in [[protein synthesis]].  Since then, much research has been conducted to modulate steps in the gene expression process. These steps include [[transcription (genetics)|transcription]], [[RNA splicing]], [[translation (biology)|translation]], and [[post-translational modification]] which are used to control the chemical and structural nature of proteins.<ref name="Berk2007">{{cite journal |vauthors=Berk V, Cate JH| title = Insights into protein biosynthesis from structures of bacterial ribosomes | journal = Curr. Opin. Struct. Biol. | volume = 17 | issue = 3 | pages = 302–9 |date=June 2007 | pmid = 17574829 | doi = 10.1016/j.sbi.2007.05.009 }}</ref> Moreover, genetic engineering gives engineers the ability to directly manipulate the genetic materials of organisms using [[recombinant DNA]] techniques. The first recombinant DNA molecule was created by [[Paul Berg]] in 1972 when he combined DNA from the monkey virus [[SV40]] with that of the [[lambda phage]].<ref name="pmid4342968">{{cite journal |vauthors=Jackson DA, Symons RH, Berg P| title = Biochemical method for inserting new genetic information into DNA of Simian Virus 40: circular SV40 DNA molecules containing lambda phage genes and the galactose operon of Escherichia coli | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 69 | issue = 10 | pages = 2904–9 |date=October 1972 | pmid = 4342968 | pmc = 389671 | doi =  10.1073/pnas.69.10.2904| bibcode = 1972PNAS...69.2904J | doi-access = free }}</ref>

Experiments on hereditary material during the time of the Hershey–Chase experiment often used bacteriophages as a [[model organism]].  Bacteriophages lend themselves to experiments on hereditary material because they incorporate their [[genetic material]] into their [[host cell]]'s genetic material (making them useful tools), they multiply quickly, and they are easily collected by researchers.<ref name=OConnor />