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Miescher
Miescher collected bandages from a nearby clinic and washed off the pus. He experimented and isolated a new molecule – nuclein – from the cell nucleus.When working with the white blood cells miescher discovered that the nuclein was rich in phosphorous and was also acidic.That's why it was named nucleic acid, a name DNA still has today. -
Chargaff
Chargaff discovered that adenine and thymine go together as base pairs as well as guanine and cytosine. He also discovered the number of purines always equal the number of pyrimidines. His discoverys are call Chargaff's Rules. By separating DNA from different organisms Chargaff discovered the amount of the nitrogenous bases in each organism and created a table to further explain why the base pairs go together. -
Franklin
Working with a student, Raymond Gosling, Franklin was able to get two sets of high-resolution photos of crystallized DNA fibers. She used two different fibers of DNA, one more highly hydrated than the other. From this she deduced the basic dimensions of DNA strands, and that the phosphates were on the outside of what was probably a helical structure.She presented her data at a lecture in King's College (which is important because James Watson attended this college) -
Hershey-Chase
Hershey and chase studied a bacteriophage that was composed of a DNA core and a protein coat. They grew viruses to determine which part of the virus entered the bacterial cell. They found that the part that entered was DNA, resulting in an experiment that covinced many scientists that DNA was the genetic material found in genes in all living cells. -
Watson and Crick
Using available X-ray data and model building, Watson and crick solved the structure of DNA. The two showed that each strand of the DNA molecule was a template for the other. During cell division the two strands separate and on each strand a new "other half" is built, just like the one before. This way DNA can reproduce itself without changing its structure except for occasional errors, or mutations. -
Meselson & Stahl
-tested the hypothesis of dna replication
-the experiment showed tha dna replicates using the semiconservative model meaning that a double helix seperates so tha each old strand serves as a templet for each new strand resulting in two new helices each containing one old and new strand.
