Genetics Timeline

  • Gregor Mendel

    Gregor Mendel
    Gregor Mendel bred pea plants to find the ways parents pass traits to their offspring. He cross fertilized several generations of peas plants and discovered how traits are recessive of dominant, He founded the basic principles of genetics.
  • Willam Bateson and Reginald Punnett

    Willam Bateson and Reginald Punnett
    William Bateson and Reginald Punnett were performed a dyhybrid cross on pea plants. The results produced were different from the results they expected acorrding to Mendel's principles of genetics. They didn't know it then but they had discovered linked genes, which follow different patterns.
  • Thomas Hunt Morgan

    Thomas Hunt Morgan
    Theomas Hunt Morgan crossed two fruit flies, a wild type fruit fly and and a fruit fly with a black body and vestigal wings. His results included recombinant phenotypes along with the expected parental phenotypes. He discovered crossing over.
  • Archibald Garrod

    Archibald Garrod
    Archibald Garrod discovered how enzymes and protiens are influenced by genes. He backed up his hypothesis by using the exampale of alkaptonuria. Alkaptonuria is when urine apears red because afflicted individuals lack the enzyme to break alkapton, its genetic, proving his hypothesis to be correct.
  • Fredrick Griffith

    Fredrick Griffith
    Fredrick Griffith studied two bacterias. One pathogenic (diseased) and one harmless strain. He found that when he killed the pathogenic strain then mixed it with the harmless the harmless strain bcame pathongenetic. He discovered DNA and its ablility to transform cells.
  • George Beadle and Edward Tatum

    George Beadle and Edward Tatum
    George Beadle and Edward Tatumm were working with breadmold. They were experimenting with strains that couldn't grow and found that each strain lacked an essential enzyme in the metabolic pathway.The came up with the one gene- one enzyme hypothesis. It says that one gene is linked to and controls the production of one enzyme.
  • Erwin Chargaff

    Erwin Chargaff
    Erwin Chargaff looked at the amounts of adenine, thymine, guanie, and cytosine in different species. He found that the amount of adenine is always equal to the amount of thymine, and that the amount of guanine is always equal to the amount of cytosine.
  • Aflred Hershey and Martha Chase

    Aflred Hershey and Martha Chase
    Alfred Hershey and Martha Chase used different radioactive isotope of Ecoli, They mixed non radioactive T2 and radioactive T2.They then injected just protien, the T2 stayed non radioactive. But when the injected DNA it changed. The proved that DNA was responsible for inheritance.
  • Maurice Wilkins and Rosalind Franklin

    Maurice Wilkins and Rosalind Franklin
    Maurice Wilkins and Rosalind Franklin took a clear picture of DNA. They discovered that it was a double helix.
  • James Watson ans Francis Crick

    James Watson ans Francis Crick
    James Watson ans Francis Crick saw the picture Franklin took of DNA that showed it to be a double helix. The constructed a model, and figured out that A always pairs with T, and C always pairs with G. The discovered the structure of DNA
  • Marshall Nirenberg

    Marshall Nirenberg
    Marshall Nierenberg was working on deciphering the genetic "code". He made an RNA molecule by connecting identical RNA nucleotides with uracil bases. There was only one condon UUU. He discovered that UUU is specific to phenylaline. From his reasearch the condons of all amino acids were found