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Friedrich Miescher
Friedrich Miescher discovered a DNA through a substance called nuclein. He found nuclein by taking used bandages that contained pus on them and examined the cells on the sample. He later found out that the nuclein was comprised of a cell's DNA and proteins. He then published a book stating his discoveries, This helped us by creating what we now know as the fundamental in the cell: DNA. This also started a chain of research to further explore DNA and helped us achieve where we are today. -
Erwin Chargaff
Erwin Chargaff analyzed how the bases of DNA were compromised and that the complementary base pairs (A and T/C and G) had equal amounts of each and different species had different amounts of the bases. He discovered this by studying different species' Dna bases and realized that there were even amounts of A and T along with C and G. He also found out that different species had different amounts of the bases. This helped us understand how the four bases correlate to each other and base pairing. -
Rosalind Franklin
Rosalind Franklin discovered information about the DNA molecule using a special technique called X-ray diffraction. Rosalind first purified a generous amount of DNA and stretched the Dna fibers in a glass tube. She did this so most of the Dna strands were parallel. She then used aimed a X-ray beam at the DNA samples and recorded a pattern that occurred in the X-ray screening. This helped us add to our current knowledge of DNA by showing that the DNA is twisted around each other in helix shape. -
Hershey & Chase
Hershey & Chase confirmed that the genetic material that made up a virus was comprised of DNA, not protein. They discovered this by growing viruses in cultures containing radioactive isotopes of phosphorus. They then mixed this bacteria with healthy cells and waited for the virus to inject itself into the other cell. When they separated the virus and cell they found DNA instead of what they expected to find: protein. This has helped us by helping us understand that DNA is in every kind of cell. -
Watson and Crick
Watson and Crick discovered what the double helix structure of DNA looks like and soon published this picture. Watson and Crick used a X-ray and model building to discover the composition of the DNA molecule. They were also inspired by many other scientist's previous work, such as Franklin, Chargaff, and Hershey & Chase. This discovery adds to our current understanding of DNA by showing us what a the most up-to-date DNA molecule looked like. -
Meselson & Stahl
Meselson & Stahl tested the three possible types of DNA replication and discovered that the semiconservative model was how DNA replicated. They found this by growing E-coli is a broth comprised of a heavy isotope of nitrogen. The DNA then took up the nitrogen and grew new substances including DNA. The E-coli then grew and in the fourth generation of E-coli, all of the previous generations had the exact same replication process. This helped us better understand DNA replication and its process.
