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Gregor Mendel
Experiment:
Mendel self-pollinated peas to ensure they were true breeding. Then he crossed pollinated the self-pollinated peas. Then the cross-pollinated peas were allowed to self polliate.
Contribution:
Hes is the creator of The Principle of Segregation and The Principle of Independent Assortment. -
William Bateson and Reginald Punnett
Experiment:
They were working with two characteristics in sweat peas, flower color and pollen shape. They crossed doubly heterozygous plants (PpLl) that exhibited the dominant traits: purple flowers and long pollen strains. The corresponding recessive traits are red flowers.
Contribution:
He discovered linked genes and that genes can be located on the same chromosome. Also created the Punnett squares. -
Thomas hunt Morgan
Experiment:
Morgan crossed a wild-type fruit fly (gray body and long wings) and a fly with a black body and undeveloped, or vestigial wings.
Contribution:
Gene mapping and crossing over to determine offspring, sex-linked traits, and recombination frequency. -
Archinbald Garrod
Experiment:
Idea of inherited diseases. He hypothesized that an inherited disease reflects a person's inability to make a particular enzyme. He gave as on example the hereditary condition called alkaptomuria. He responded that normal individuals have and enzyme that breaks down alkapton.
Contribution:
He found the relationship between ganes and proteins and that genes dictate traits through proteins. -
Frederick Griffith
Experiment:
Griffith studied tow variteties of the bacterium, a pathogenic one and a variant that was harmless. He found that when he killed the pathogenic bacteria with heat and then mixed the cell remains with living bacteria of the harmless varity, some of the living cells were converted to the pathogenic form.
Contribution:
He is the person that discovered transformation. -
George Beadle and Edward Tatum
Experiment:
They studied strains of the mold that were unable to grow on the usual simple growth medium. Each of the mutants turned out to lack a n enzyme in a metabolic pathway that produced some molecule the mold needed.
Contribution:
They discovered the relationship between genes and enzymes. -
Erwin Chargaff
Experiment:
He split cells to be able to look at DNA more closely.
Contribution:
He discovered that the amount of adenine in the DNA of any one species was equal to the amount of thymine, and that the amount of guanine was equal to that of cytosine. Also he discovered base-pairing rules. -
Alfred Hershey and Martha Chase
Experiment:
They allowed the protein-labled and DNA-labled batches of T2 to infect seperate samples of nonradioactive bacteria. They agitated the cultures in a blender to shake loose any parts of the phages that remained outside of the bacteria cells. They spun the mixtures in cantrifuse. The phages and phage parts remained suspended in liquid. They measured and compared the radioactivity in the pellet and the liquid.
Contribution:
They discovered that DNA was genetic material. -
Maurice Wilkins and Rosalind Franklin
Experiement:
They took X-rays crystallographic photographs of DNA.
Contribution:
They discovered that DNA was a helix. -
James Watson and Francis Crick
Experiment:
They formed wired models of the nucleotids. (Construct double helix that conformed to Franklin's data) Watson tried putting back bones on the outside and forced the nitrogenous bases to swivel to the interior of molecules.
Contribution:
They discovered that DNA was a double helix made of 2 polynucleotide strands. -
Marshall Nirenberg
Experiment:
He produced RNA suply of uracil. He added poly uracil RNA into a cell-free extract of Eschericha coli which contained DNA,RNA, ribosomes for protein synthesis. He added DNase so no other proteins would form other than synthetic RNA. He added 1 amino acid and 19 unlabled amino acid to the extract. The resulting protein was radioactive.
Contribution:
He founded the genetic code for phenylalanine, first step of condons in genetic code, and the first dmonstration of messenger RNA.
