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Thomas Morgan established the chromosomal inheritance theory. At Columbia University, he started a lab with flies, this lab helped with studying genetic variations, He made many important discoveries through this lab having to do with genetics and chromosomal inheritance,
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In 1869, Friedrich Miescher 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. Although Miescher did most of his work in 1869, his paper on nuclein wasn't published until 1871.
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Hermann was a geneticist who was very interested in the physical and chemical aspects of genes. In 1920, he made a very important discovery having to do with x-rays and mutations in a fruit fly. This was important because it shows how x-rays damage chromosomes which will produce a mutation.
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While trying to find a cure for pneumonia, Griffith made a major scientific discovery. Griffith's famous 1928 Experiment showed us that bacteria can distinctly change their function and form. Before his experiment, scientists believed that bacteria were fixed and unchangeable.http://www.biologyjunction.com/Webquest%20for%20DNA_files/image002.jpg
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He and his coworkers discovered that DNA carries a cell's genetic material and can be altered throguh transformation.
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Erwin Chargaff also worked to develop ideas and investigations on the compositions of DNA. He discovered crucial facts that directly led to the illustrations of DNA's molecular structure. Chargaff established rules which state that in DNA there is an equal percentage of Adenine as Thymine and Guanine as Cytosine. These pairs also could never be crossed paired.
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Maurice Wilkins and Rosalind Franklin were biophycists and x-ray crystallographers. Together they made crucial contributions to the discover of DNA's structure. Through there studies and detail measurements, it was suggested that DNA was helical in structure.
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In 1952, Linus showed a triple stranded helix in DNA. He had the nitrogenous bases facing out and phosphate groups facing in and three different strands intertwined. However, since the oxygen bases were all facing in, the strands repelled each other, making the triple stranded helix, actually work.
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Alfred Hershey and Martha Chase were additional scientists who validated that DNA was the genetic coding material. In their "blender' experiment they used phage-bacteria viruses to demonstrate and prove this theory.
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James Watson and Francis Crick used the findings of Franklin and Wilkins, to conduct their own studies on DNA's actual structure. They used what was already chemically known about DNA, and published the 1st accurate model of its structure in 1953. Their model displayed a double-helix feature, and presented concepts on how DNA replicates and codes hereditary information.
