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Gregor Mendel finds out how parents pass on discrete inheritable traits
He cultured pea plants because they were easily controlled for mating and had readily distinguishable varieties. It showed how parents pass off their traits to their offspring -
William Bateson and Reginald Punnett discovered inheritance patterns
They experimented with two characteristics in sweet peas, flower color and pollen shape, and discovered inheritance patterns that were totally inconsistant with Mendelian principles -
Thomas Hunt Morgan finds out what crossing over is
He bred fruit flies and discovered linked genes and what crossing over was. -
Archibald Garrod proved that majority of genetic defects are caused by a single gene
He concluded that alkaptonuric people don't have the enzyme alkapton, which causes dark urine, and is a genetic defect. This proved that the majority of genetic defects are caused by a single gene -
Frederick Griffith proved that bacteria could change shapes and there shapes changed by transformation.
He attempted to prevent pneumonia infections by combining a lethal pneumonia cell with a non- lethal pneumonia cell, which caused the non lethal cells to become lethal. This proved that bacteria could change shapes by transformation. -
George Beadle and Edward Tatum discovered that genes dictate the production of a specific enzyme and all proteins
They experimented by growing orange bread mold and examined strains that wouldn't grow on the usual simple growth medium. -
Edwin Chargaff discovers that in a DNA molecule; Adenine=Thymine and Guanine=Cytosine
He studied a lot of different oraganisms and found that adenine equaled thymine and guanine equaled cytosine in its DNA. -
Alfred Hershey and Martha Chase confirmed the DNA genetic material and proved that genetic material infects and DNA was not a protein
They infected E-Coli with T2 phage and labeled it with radioactive material so he could tell what was being infected, and proved that genetic material infects and isn't a protein. -
Maurice Wilkins and Rosalind Franklin found that DNA was at least a helix shape
They took x-ray crystallographic photographs of protein structures and found that DNA was a helix. -
James Watson and Francis Crick determined that DNA was a double helix made of two polynucleotide strands
They looked at the photo taken by Rosalind Franklin closer and found that DNA was a double helix and that it was made of two polynucleotide starnds. -
Marshall Nirenberg cracks the genetic code
He cracked the genetic code by using sap in a test tube and using controlled RNA and DNA.
