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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. He determined that nuclein was made up of hydrogen, oxygen, nitrogen and phosphorus and there was an unique ratio of phosphorus to nitrogen. He was able to isolate nuclein from other cells and later used salmon sperm as a source. He is the discovery of DNA. -
Hershey & Chase
Hershey and Chase did their famous blender experiment which showed that DNA is the genetic material. In parallel experiments, bacteriophages containing either 32P-labeled DNA or 35S-labeled proteins were allowed to infect bacteria. Following infection, the cultures were agitated in a blender to detach viruses from the bacterial cells and then centrifuged. Bacterial cells formed a pellet at the bottom, while the viral particles remained in the supernatant. -
Watson and Crick
On 1953, scientists Watson and Crick announce that they have determined the double-helix structure of DNA, the molecule containing human genes. In the 1950s, Watson and Crick were only two of many scientists working on figuring out the structure of DNA. According to their findings, DNA replicated itself by separating into individual strands, each of which became the template for a new double helix. They used X-ray photographic to see and identify the DNA and how it works. -
Chargaff
In 1950 Erwin Chargaff discovered that the chemical units of DNA, known as bases, always occurred in pairs. Chargaff's work lead directly to the discovery of the double-helix structure of DNA, by James Watson and Francis Crick, in 1953.Erwin Chargaff’s research paved the way for the discoveries of DNA’s structure and its method of replication. His observation that DNA varies from species to species made it highly credible that DNA was genetic material. -
Franklin
Rosalind Franklin a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite.The DNA work achieved the most fame because DNA plays essential roles in cell metabolism and genetics, and the discovery of its structure helped scientists understand how genetic information is passed from parents to children. -
Meselson & Stahl
Meselson and Stahl proved that the semi-conservative theory was correct. they did so by conducting experiment by choosing two isotopes of nitrogen because it is an essential chemical component of DNA; therefore, every time a cell divides and its DNA replicates, it incorporates new N atoms into the DNA of either one or both of its two daughter cells.
