= Julius Marmur
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{wiki}
= J. Marmur
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{synonym}
\b[Julius Marmur] was a <biochemist> whose work included DNA isolation, strand reassociation and <DNA hybridization>. His institutional biography at Albert Einstein College of Medicine identifies his collaboration with <P. Doty> at Harvard and his later research in <yeast> genetics.<Julius Marmur profile at Albert Einstein College of Medicine>[About Dr.Julius Marmur]{ref}
Marmur's contribution linked preparing intact <DNA> with testing its physical behavior. Purification makes it possible to compare changes in the nucleic acid itself rather than changes caused by a heterogeneous cell extract. <DNA melting> and subsequent pairing experiments then ask whether separated complementary strands can recover an associated structure. Isolation, strand separation and sequence-dependent reassociation are distinct experimental questions.
In the1962 thermal-denaturation study with Doty, the apparatus measured <absorbance> as a function of sample temperature. The authors used the midpoint of the <hyperchromic effect> and compared it with <GC content> determined independently. They corrected for thermal expansion of the solution, an example of separating a molecular absorption change from the changing concentration during heating.<Determination of the base composition of deoxyribonucleic acid from its thermal denaturation temperature by J. Marmur and P. Doty>[Printedpp.109–110, abstract and Materials and Methods]{ref}
The resulting approach made bulk optical measurements informative about DNA composition and structural transitions. It did not directly read the order of bases along a strand: composition, pairing behavior and <nucleic acid sequence> remain different descriptions.
\Image[https://einsteinmed.edu/uploadedImages/education/phd/Julius%20Marmur-1.bmp]
{title=Julius Marmur}
{id=image-julius-marmur-einstein}
{description=Externally hosted portrait explicitly identified in Albert Einstein College of Medicine's institutional biography.}
{width=250}
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