DNA Timeline

Shairah Carpio Period 4 December 7 2012

Main

Gregor Mendel

1863 - 1866

His study on pea plants lead to the laws of inheritance in which genes are known to be inherited by parents.

Thomas Hunt Morgan

1904

His study on fruit flies led to the chromosomal theory of inheritance. He studied the genetics that underlie inheritance.

Frederick Griffith

1928

His experiment concluded that protein was not the genetic material and hinted that DNA is the genetic material that caused the bacterial transformation.

Avery, McCarty and Macleod

1944

Read Griffith's experiment and made an experiment with injected rough bacteria. The rats with digested proteins lived, while those of digested DNA didn't. Showed that DNA was the transforming material

Edwin Chargaff

1950

Came up with the percentages of nucleotide bases. Showed that the number of A=T and C=G. This is consistent with the DNA structure Watson and Crick formulated because the purines are paired with pyrimidines

Linus Pauling

1951

Came up with the triple-helix DNA model. This model motivated Watson and Crick to solve the real structure of the DNA before Pauling.

Hershey and Chase

1952

By testing with radioactive protein and radioactive DNA, they found evidence that DNA alone is the hereditary material because DNA entered bacteria. Motivated Watson and Crick to study DNA structure

Maurice Wilkins

1952

Helped Watson and Crick by showing them Photo 51, helping them determine that the DNA is a double helix.

Rosalind Franklin

1952

Discovered the A and B forms of DNA. Used xray crystallography to determine the double helix structure of DNA. Her picture of DNA is what Watson and Crick used to modify their structural model.

Watson and Crick

1953

Made the structure model of DNA. Helped future scientists study the DNA better.

Meselson and Stahl

1958

Designed an experiment that led to the semiconservative replication model of DNA, disproving the conservative model. Shows that two original DNA strands separate and new complementary strands result