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Frederick Griffith
Griffth injected mice with regular pneumonia and they developed pneumonia,other mice were injected with heat-killed type of pneumonia.None of the mice developed pneumonia.When he injected mice with both types,the mice did develope pneumonia.The 1st type had made protective capsules for themselves,transforming themselves into type 2.They had acquired the characteristics from the dead Type 2.His historical one-page paper carried the first really accepted demonstrations of bacterial transformation. -
Oswald Avery
He discovered the chemical composition of the substance that allowed streptococcus pneumoniae (strep throat). Like most scientists, he expected that the substance would be a form of protein, but instead Avery found that it was entirely made up of DNA. This overturned the accepted understanding that DNA was relatively unimportant in passing genetic characteristics, and showed that genes are made not of protein but of DNA. -
Linus Pauling and Robert Corey
Corey and Pauling made the famous alpha helix model for protein structures. WHile they were expirementing, Pauling developed the useful method of tinker-toy modeling to help himself and others visualize and understand the molecules. This work formed the basis for the discovery of the double helix structure of DNA by James Watson and Francis Crick. -
Alfred Hershey and Martha Chase
These scientists put radioactive protien in a bacterum and blended it and found that the liquid was radioactive, not the cell parts. They then put the radioactive pelet in the DNA, blended it and discovered that the radiactive material was in the cell parts, not the liquid. They found that DNA is what caused the production of other phages in the cell, not the protiens. -
Erwin Chargaff
Chargaff and his co-workers calculated the amount of adenine in DNA was equal to the amount of thymine. They also discoverd that the amount of cytosine is equal to the amount of guanine. They discovered and contributed that adenine always bonded with thymine and cytosine always bonded with guanine. So with every adenine there is a thymine, and with every cytosine there is a guanine. -
James Watson and Francis Crick
They used x-ray diffraction data collected by Rosalind Franklin and proposed the double helix or spiral staircase structure of the DNA molecule. Their article, Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid, is celebrated for its treatment of the B form of DNA, and as the source of Watson-Crick base pairing of nucleotides.They were awarded the Nobel Prize in Physiology or Medicine. -
Seymour Benzer
After Watson and Crick published their model of DNA, Benzer hatched his plan to get inside the gene by using bacteriophage with mutated genes. Max Delbrick ridiculed the plan and told Benzer "you must have drunk a triple highball before writing this." Benzer's 5-year-old daughter Martha liked the plan better and sketched her vision of two phages infecting a bacterium. In 1971, Benzer received the Lasker Award for this "brilliant contribution to molecular genetics." -
Arthur Kornberg
Kornberg discovered that DNA polymerases are best-known for their feedback role in DNA replication, in which the polymerase "reads" an intact DNA strand as a and uses it to synthesize the new strand. -
Evelyn Witkin
She worked on DNA response to UV radiation, laying the foundation for the discovery of the molecular mechanisms by which UV-induced genes may be repaired. Witkin concentrated on understanding the cellular response to UV throughout her career. -
Sydney Brenner
Sydney Brenner is one of the leading pioneers in genetics and molecule biology. Among his many notable discoveries, Brenner established the existence of messenger RNA and demonstrated how the order of amino acids in proteins is determined. -
Marshall Nirenburg
In Nirenberg's expirament, he synthesised an artificial RNA molecule and linked it to an identical molecule. He added the poly-U (UUU) to the amino acide, phenylalanine. The contribution that he made was that he discovered that the poly-U specifies to the acid phenylalanine. This also contributed to the discovery that the A, U, C, or G are grouped in threes to create a specific amino acid. -
Roy John Britten
Britten showed that eukaryotic genomes have many repetitive, noncoding DNA sequences. -
Hamilton Smith and Daniel Nathans
Smith and Nathans discovered that a restriction enzyme is an enzyme that cuts double-stranded or single stranded DNA at specific recognition nucleotide sequences known as restriction sites. -
Fred Sanger
He determined the sequence of amino acids in a protein, that 51 amino acids of the insuline protein go in a specific order. In the 1975 he developed a method to determine the exact sequence of nucleotides on a gene. -
Walter Gilbert
Together with Allan Maxam, Gilbert developed a new DNA sequencing method. His approach used genes built up from the nucleotides rather than from natural sources. -
Kary Mullis
Mullis invented the polymerase chain reaction (PCR), a technique that amplifies specific DNA sequences from very small amounts of genetic material. PCR has revolutionized DNA technology by allowing scientists to produce an almost unlimited amount of purified DNA molecules for analysis or manipulation. -
Alec Jeffreys
Jeffreys found that DNA profiles are encrypted sets of numbers that reflect a person's DNA makeup, which can also be used as the person's identifier. -
Thomas Cech
Cech and his research group did the work leading to the discovery that RNA can self-splice and thus can act as a ribozome. -
Dolly the Sheep
Dolly the Sheep was a female domestic sheep, and the first mammal to be cloned from an adult somatic cell, using the process of nuclear transfer. -
Human Genome Project
An international scientific research project with a primary goal of determining the sequence of chemical base pairs which make up DNA, and of identifying and mapping the approximately 20,000–25,000 genes of the human genome from both a physical and functional standpoint.
