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Frederick Griffith
Frederick Griffith, a British scientist, was originally working to find a cure for pneumonia when he discovered and proved that bacteria can in fact change their function as well as appearance. His experiment began with injecting two strains of bacteria into mice and was later able to conclude that bacteria can get DNA through transformation. One of the bacteria that he discovered was what caused pneumonia so in the end he managed to find what he was looking for in the first place. -
Barbara McClintock
McClintock is seen as a woman who changed the world. Her discoveries affected research regarding cancer and genetic engineering for the better. However, she is best remembered for discovering “jumping genes” (genetic transposition). After discovering that genes had the ability to be mobile, her interest grew and later was able to prove the existence of transposons, DNA sequences that can change positions in chromosomes. They have proved to be crucial in plant evolution. -
Oswald Avery, Maclyn McCarty & Colin MaCleod
They were initially interested in Griffith’s discovery and had decided to look further into it. While for the most part they did not conduct their experiments together, they managed to identify DNA as the transforming principle; it is what allows the bacteria to alter its function and appearance. During their time they experimented with enzymes and DNA as well. They concluded that genes were made up of DNA and that when bacteria was treated with certain enzymes, transformation would not occur. -
Erwin Chargaff
Chargaff studied at University of Vienna and graduated with a Ph D in chemistry. He discovered that the proportions of bases in DNA can vary depending on the species in which the DNA is coming from. In his life he proposed Chargaff’s rules. The frequency of A equals the frequency of T and the frequency of G equals the frequency of C. These rules influenced Crick and Watson’s work when experimenting with mice. -
Alfred Hershey & Martha Chase
Scientists had been wondering for a long time whether protein was a genetic material. Hershey was a phage geneticist and his assistant was Martha Chase, staying at Washington University. Hershey and Chase were able to prove that while it was not a genetic material, DNA was. They were most well known for the blender experiment. This experiment was what proved that DNA served as a genetic element for phages. They also concluded that phages were only able to inject their DNA into host bacteria. -
Rosalind Franklin & Maurice Wilkins
Franklin and Wilkins influenced Crick and Watson's discovery with their own discovery of DNA structure. They created images of DNA using X-ray crystallography, first broached by Maurice.. Thus, the famous Photo 51 revealing an example of DNA structure had surfaced. Any credit that they rightfully deserved was given to Crick and Watson after their breakthrough with the double-helix structure. The whole unfortunate situation sparked sexism in the science field. -
Linus Pauling
Linus Pauling was known for many things, one of which being the founder of molecular biology. He had influenced Crick and Watson's DNA double helix discovery with his discovery of spiraling protein structures. He won more than one Nobel Prize in chemistry for his research into the nature of chemical bonds and structures. -
James Watson & Frances Crick
Being influenced by many other scientists, Watson and Crick received the credit for discovering the double-helix structure of DNA. Wilkins and Franklin's Photo 51 originally revealed the DNA structure and through Watson and Crick's studies they managed to receive the credit for the discovery. They had a couple failed attempts like when building a triple-helix structure but in the end they were able to receive a Nobel prize for their work and became famous. -
Matthew Meselson & Franklin Stahl
Meselson and Stahl had met in a course led by Watson and Crick. They later discovered the semi-conservative replication of DNA. This means that each strand within a DNA molecule can serve as a template for a new strand. It can make a copy of itself leaving an old strand and creating a new one. Their discovery regarding this replication was published during 1958 and they can also receive credit for helping certify Crick and Watson's concept of the double-helix DNA structure. -
Friedrich Miescher
At the University of Tubingen, Friedrich Miescher isolated nuclein, a substance in which contains the nitrogen and phosphorus in the nuclei of white blood cells. He is well known and credited for this discovery and it later became known as nucleic acid after separating it into protein and acid components. Miescher also became one of the earliest scientists to support the idea that carbon dioxide concentration in blood is what regulates breathing. -
Paul Berg
Berg graduated from Stanford University becoming the first to prove the chance of making recombinant DNA with his first being generated in 1972. The recombinant DNA was a molecule made from parts of various organisms. It could also be referred to as "hybrid DNA." With the use of enzymes, DNA fragments are removed from their positions in the chromosomes and inserted elsewhere into other chromosomes with ligases, an enzyme. -
Frederick Sanger
Sanger was a British scientist who became the first to find the DNA sequence of insulin. The Sanger method laid the foundation for the Human Genome Project. The Sanger method was a method for sequencing DNA. Sanger, working alongside Coulson, published a method called the plus minus method in 1975. He received two Nobel prizes, one for developing methods for sequencing amino acids. -
Kary Mullis
Kary Mullis discovered the polymerase chain reaction. The PCR is a method or technique used to create copies of segments of DNA strands. It allows scientists to make multiple copies of a specific targeted segment in DNA and be able to study it in much better detail. In 1983, through the work of plenty of previous scientists, Mullis was able to achieve the first practical demonstration of the PCR. Mullis filed a patent on the PCR in 1985 and the technique was finally published months later. -
J. Craig Venter
Venter was an American biotechnologist and receives credit for introducing techniques regarding genetic and genomic research. He is really known for leading the first draft sequence of the Human Genome Project. The HGP's goal was to discover the base pairs and overall DNA sequence making up human DNA. In 2003 the finalized and accurate human genome sequence was published.
