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Genetic Contribuitions
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Gregor Mendel
Gregor Mendel was a monk who experimented with pea plants. He self pollinated peas to ensure they would be true bred. Then he cross pollinated the p generatoin and the F1 generation were allowed to self pollinate. His contribution was the Laws of Inheritance which included the principle of segregation and the principle of independant assortment. -
William Bateson and Reginald Punnett
These two scientists crossed doubly heterozygous plants that exhibited dominant traits for purple flowers and long pollen grains. By doing this they foud that they didn't get the expected ratio of 9:3:3:1. By doing this experiment they discovered linked genes, and this was their contribution to genetics. -
Thomas Hunt Morgan
Thomas Hunt Morgan mated a gray fly with long wings with a black fly with vestigal wings. His result had 17 percent of recombinates. He also saw that the flys with red eyes were females and the flys with white eyes were males. By doing this experiment he discovered crossing over and sex linkage. Those two things were his contribution. -
Archibald Garrod
Archibald thought that genetic defects cause many inherited diseases. Then he foud that normal individuals have an enzyme that breaks down alkapton and that the patients he saw did not. He found that genes dictate phenotypes through enzymes and that was his contribution to the science of genetics. -
Frederick Griffith
Griffith worked at the ministry of health in London. He studied 2 bacterias; one that was not harmful and one that caused disease. He killed the pathogenic bacteria with heat and then mixed the cell remains with living bacteria of the harmless variety. Griffith then noticed that some cells ended up turning pathogenic. By doing this experiment he contributed the breakthrough of transformation. -
George Beadle and Edward Tatum
Beadle and Tatum studied mold that was not able to grow on the usual medium. So they found that it lacked an enzyme in a metabloic pathway that the mold needed to grow. They found the one gene-one enzyme hypothesis. This was their contribution to genetics. -
Erwin Chargaff
Erwin Chargaff used paper chromatography and ultraviolet spectroscopy to discover that the amount of purine bases in DNA always equaled the amount of pyrimidine bases. Chargaff's contribution was that the amount of Thymine always equaled the amount of Adenine and Cytosine always equaled the amount of Guanine. -
Maurice Wilkins and Rosalind Franklin
Wilkins and Franklin used crystallographics to photograph DNA molecules. By doing this they found the DNA helix. -
Alfred Hershey and Martha Chase
Alfred Hershey and Martha Chase used a 4 step experiment. Step one was to mix radioactive phages with bacteria and let the phages infect the bacteria. Step two was to use a blender and agitate the phages to seperate the outside and inside of the bacteria cells. Next they centrifuged the mixture and the last step was to measure the amount of radioactivity in the pellet and the liquid. They discovered that injected DNA molecules caused cells to produce more phage DNA and proteins. -
James Watson and Francis Crick
Watson and Crick constructed a DNA double helix and it was constructed with the DNA bases in the specific order they had to go in. So adenine with thymine and guanine with cytosine. Their contribution was the DNA double helix and they found it had a 2 nm diameter and 2 polynucleotids. -
Marshall Nirenberg
Nirenberg added RNA to a cell free of E. Coli and then added DNase which break down DNA so no proteins are produced. Nirenberg then added one radioactive amino acid and 19 unlabeled proteins. He found the genetic code on RNA for phenylanine. He translated the genetic code.
