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Friedrich (Fritz) Miescher's Discovery
-He did most of his work in 1869, but it wasn't published until 1871
-Fritz discovered nuclein or nucleic acids (found in the nucleus) and found that it was made of hydrogen, oxygen, nitrogen and phosphorus
-He made this discovery by taking used band aids with pus on them, removing the pus, and studying the white blood cells (he later used salmon sperm in his research instead of band aids)
-Nucleic acids are what make up DNA -
Erwin Chargaff
-In 1950 Erwin Chargaff discovered crucial facts that led to the DNA's structure
-By running experiments he discovered that the nitrogenous bases A,G,T, and C were somewhat equal
-He discovered that A is very similar and almost equal to T and same goes with G and C
-This is when he created the Chargaff's Rule: A=T and G=C
-He semi proved this because after examining both human and bacteria cells followed this rule but no one knew why
-That is how he contributed to our understanding of DNA today -
Rosalind Franklin
-In the 1950's Rosalind Franklin used X-ray diffraction to get information about the structure of DNA
-Her X-ray photos showed that strands of DNA are twisted around each other in a helix-shape
-Rosalind showed and discovered that DNA is made of two strands from her X-ray photos
-One other clue she discovered were that the nitrogenous bases in DNA were found towards the center of the DNA molecule
-Without the X-ray photos scientists would have never discovered the structure of DNA -
Hershey & Chase's Discovery
-They demonstrated that DNA, rather than proteins, is the carrier of genetic information
-Hershey and Chase, tracked the transfer of proteins and DNA between a virus and host, they needed to show that a portion of the protein mass was transferred to the interior of the bacterium. So they put the bacteria in a blender and separated the protein shells from the bacteria and then put in a centrifuge to see where everything was. -
Watson & Crick
-In 1953 Watson saw a copy of Franklin's X-ray photo
-After trying for years to build a model of DNA Watson and Crick came to realize what they were missing when Watson explained Franklin's X-ray photo
-They had discovered that the two strands of DNA are "antiparallel" and due to this the nitrogenous bases on both strands meet in the center of the molecule
-They also discovered that the model is held by hydrogen bonding
-With this information they completed the current DNA model today -
Meselson & Stahl's Discovery
-Their research paper was published in 1958
-The discovery was made through various experiments that had lots of 'delightfully clean data.' But I was unable to find what the experiments consisted of other than a lot of pipetting DNA. They also had 3 theories of how DNA was replicated: semi conservative, conservative, and dispersive. Of the 3, only semi-conservative proved correct
-Their research helped solidify the discovery of the double helix by James Watson and Francis Crick
