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Gregor Mendel
Experiment:
Wanted to cross fertilize pea plants
1.First removed stamens from purple flower
2.Transfered pollen from stamens of white flower to the carpel of the purple flower
3.Pollinated carpel mature into pod
4.Planted seeds from pod
Contribution:
Discovered different alleles, two genes from each parent, allele pairs seperate during meiosis, one allel fully expressed the other no noticable effect -
William Bateson and Reginald Punnett
Experiment:
They crossed doubly heterozygous plants that exhibited the dominant traits purple flowers and long pollen grains. the corresponding rececessive traits are red flowers and round pollen.
Contribution:
Discovered linked genes -
Thomas Hunt Morgan
Experiment:
A cross between a wild type fruit fly (gray body long wings) and a fly with a black body and underdeveloped or vestigial wings
Contribution:
Discovere crossing over genetic recombination -
Archibald Garrod
Experiment:
Observed that people with alkapotonuria congential disorder, when exposed to air patients urine would turn dark red
Contribution:
Discovered that inherited disease reflects a persons inability to make a perticular enzyme -
frederick Griffith
Experiment:
Used mice to determine which bacteria would kill them
Contribution:
Discovered transformation -
George Beadle and Edward Tatum
Experiment:
Used orange bread mold unable to grow on the usual simple groth medium
Contribution:
One gene one enzyme function of an original gene is to dictate the production of a single enzyme -
Erwin Chargaff
Experiment:
Noticed a pattern in the model, he took samples of different DNA cells to find out that (A=T) and (C=G)
Contribution:
Discovered that the amount of Adenine is equal to the amount of thymine, and that the amount of cytosine is equal to the amount of guanine (base pairing rules) -
Maurice Wilkins and Rosalind Franklin
Experiment:
Took an x-ray crystallographic photograph and DNA
Contribution:
DNA was a helix -
Alfred Hershey and Martha Chase
Experiment:
Used bacteriophage composed only of DNA and protien, DNA tagged by radioactive phosphorus, protien was tagged with radioactive sulfur
Contribution:
Determined that DNA was a genetic material -
James Watson and Francis Crick
Experiement:
Tried putting the back bones on the outside and forcing the nitrogren bases to swivel to the interior of the molcule (Wire Modle)
Contribution:
Determined that DNA was a double helix made of two Polynucleotide strands -
Marshall Nireberg
Experiment:
Set up a "cell free" system with "sap" from E.Coli cells containing enzymes and an energy system added simple chains of RNA with amino acids
Contribution:
Discovered first "Triplet" sequence of three bases of DNA codes for one of the 20 amino acids that serve as the building blocks of protien.
