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Fred Griffith
By studying two different types of bacterium, he found two types of strands. A R stand, which was a harmless rough strand, and a S strand, the complete opposite. He mixed together the dead remains of a S strrand with a live R strand and the combination then the harmless R strand was transformed into a mean green mouse killing machine. This discovery led to the chase for the genetic material that determined this change. -
Oswald Avery's DNA Discovery
In his experiment he answered Fred Griffith's question. By inactivating the proteins inside the R/S bacterium strand hybrid, he made sure that the proteins were not the factor responsible thus proving DNA is the genetic factor. By building onto what Fred Griffith started he proved the existance of DNA! -
Chargoff's Rules
Chargaff studied the DNA in different species of organisms and found out that in each different organism, there was a specific amount of concentrations of the 4 bases unique to each species. However within each species, the adenine and thymine had equal concentrations and the same went to Cytosine and Guanine. These new "Rules" set a new base for the study of DNA for all scientists. -
Rosalind Franklin
She was an ambitious woman who was a crystal x-ray expert. Rosalind had much of her work improved on and confirmed by Watson and Crick. She used her Cystal X-rays to find out that the spaces in the diffractions represented not one helix structure but two! This research made the whole world confirm that DNA had a structure of a double helix and this information helped scientists to have a greater understanding of the genetic material known as DNA. -
Watson and Crick's DOUBLEHELIX!!
Watson and Crick wanted to expand their knowledge of the DNA's so they set out to find the pattern of DNA first. They discovered that DNA couldn't be as simple and repetitive as thought because that wouldn't be enough to carry information so it must be INTELLIGENT!! The nucleotides had to change in order to store more information. By using X-Ray diffractions they found out the DNA is shaped as if there was 2 helixs! This led other scientists to know the structure and base much research on this. -
Hershey and Chase Confirm!!
Alfred Hershey and Martha Chase knew that most people were still doubtful but they had an idea. They knew that viruses need to implant their genes into a host cell in order to reproduce and spread their virus. So by using specific radioactive elements they indentifyed this genetic material. It was DNA thus comfirming the fact that DNA is the genetic material and by confirming it, they let more scientists into this study.
