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Frederick Griffith
Discovered the transforming principle. He worte a paper that showed that a nonpathogenic strain of the bacterium Streptococcus pneumonaie could be induced to take on the disease-causing characteristics of a different strain, a finding which formed the foundation of the transforming principle. -
Oswald Avery
Avery collaborated with Maclyn McCarty and Colin MacLeod to discover the chemical composition of the substance that allowed pneumonia to be altered and passed to the nect generation. Avery and his colleagues found that it was entirely made up of deoxyribonucleic acid (DNA). -
Erwin Chargraff
He experimentally determined crucial facts that led directly to DNA's molecular structure. He invented Chargraff's rules which state that the number of adenine always equals the number of thymine, the number of guanine equals the number of cytosine, he number of purines (A+G) always equals the number of pyrimidines (T+C). These are the basic facts you have to know to construct an accurate model of the DNA double helix therefore he contributed to the structure of DNA. -
Alfred Hershey
Alfred D. Hershey is best known for an experiment he conducted in 1952, which showed that deoxyribonucleic acid (DNA) is the genetic material of life. Hershey and Martha Chase began a study of the contributions of the nucleic acid and protein components of phage particles to phage heredity which later showed them that DNA was the material basis for heredity, encoding each genetic characteristic as well as the program for the growth and development of progeny. -
Colin Macleod
He worked withOswald Avery, and Maclyn McCarty and together they demonstrated that DNA is the active component responsible for genetic transformation. -
Maclyn McCarty
Worked with Oswald Avery and they were the first to precipitate DNA from bacteria.They used enzymes to degrade different classes of molecules and proved that DNA was the transforming factor. -
Francis Crick
He studied eith James Watson on the structure of DNA. They used available X-ray data and model building to solve the structure of DNA. -
Rosalind Franklin
Rosalind Franklin came very close to solving the DNA structure. She took X-ray photographs of DNA. She had a meaningful role in learning the structure of DNA. -
Martha Chase
She helped prove that DNA is the molecule that carries genetic information. She was hired by Alfred Hershey to determine whether DNA or its associated protein carried the genetic information for infection, growth and development. Using radioactive tracers to mark the DNA core and the protein coat of the bacterial virus, they placed the material in a blender and turned it on. After the blender had separated the DNA and the protein, an examination showed that only the DNA had entered the bacteria. -
James Watson
James Watson's goal was to solve the DNA structure. He met Francis Crick and they began to work together. Thier first attempt toward learning its structure failed but the second attempt resulted in them putting forth the doduble helix configuration. Their model also showed how the DNA molecule could duplicate itself. -
Meselson and Stahl
They tested the hypothesis of DNA replication. They set up an experiment that demonstrated the correctness of the semiconservative model od DNA replication.
