Editing Hershey–Chase experiment (section)

===Other experiments===
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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">
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 | 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 />