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History of Genetics

History of Genetics. Pre 1920’s. Mendel- worked with pea plants and discovered the laws of heredity (work was ignored until 1900 when rediscovered) Meischer - discovered DNA, called nuclein , extracted from pus filled bandages

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History of Genetics

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  1. History of Genetics

  2. Pre 1920’s • Mendel- worked with pea plants and discovered the laws of heredity (work was ignored until 1900 when rediscovered) • Meischer- discovered DNA, called nuclein, extracted from pus filled bandages • Morgan- discovered that chromosomes control traits when he studied white eyed male mutant drosophila

  3. 1920-1949 • Muller- discovered that x-rays mutate DNA (warnings were ignored) • Beadle and Tatum- discovered that enzymes were gene products, one gene one enzyme theory, when working with Neospora (bread mold) • McClintock- discovered that genes were not stagnant and could transpose onto different chromosomes (jumping genes) when studying corn kernel color.

  4. Early 1950’s • Chargaff- discovered that the four bases ACTG are always present in a certain ratio, 1:1, A:T and G:C, called Chargaff's rule. • Hershey and Chase- showed that DNA was the molecule responsible for passing genes when studying bacteriophage. • Watson, Crick and Franklin- Watson and Crick used stolen X-ray crystallography images from Franklin’s lab to determine the double helix structure of DNA.

  5. Late 1950’s • Crick- developed the central dogma theory that explains how genes encode for proteins. • Meselson and Stahl- discovered that DNA replicates in a semi-conservative manner. One stand is conserved as a template and the other is newly synthesized during replication. • A. Kornberg- isolated the enzyme that replicates DNA, DNA polymerase, and discovered DNA could be replicated in vitro, laid the ground work for Mullis’ PCR.

  6. 1960’s • Nirenberg- cracked the universal genetic code, by studying E. coli. He determined that there were 64 codons that coded for the 20 amino acids present in all living organisms. • Jacob and Monod- were the first to understand how a gene was regulated (turned on/off) by studying the lac operon, a gene that codes for an enzyme that breaks down lactose.

  7. 1970’s • Cohen and Boyer- used restriction enzymes to make recombinant DNA, DNA that has non native genes inserted into it. • R. Kornberg- discovered chromatin structure. Determined that DNA was wound around histone proteins that accounted for its condensed packaging. • Sanger- discovered the Sanger di-deoxy method of DNA sequencing.

  8. 1980’s • Mullis- discovered that DNA could amplified, so that it could be studied better. The technique was called PCR polymerase chain reaction. • Jeffreys- developed DNA fingerprinting technique that is used in many applications. He used restriction enzymes to digest DNA into a banding pattern that is compared to a known sample of DNA.

  9. 1990’s-Present • King- discovered that chips and humans share 99% of genes. She also discovered the breast cancer gene BRCA1, was the first to link cancer to an actual gene. • Venter and Collins- Collins discovered programmed call death and they both work on the human genome project. Completely sequenced the genome for several organism including humans.

  10. Links • http://www.dnai.org/timeline/ • https://www.youtube.com/watch?v=GTiOETaZg4w • https://www.youtube.com/watch?v=CeXfh96pe08 • http://www.dnalc.org/resources/nobel/beadle_tatum.html • https://www.youtube.com/watch?v=SGViDFQ4Zjk • https://www.youtube.com/watch?v=QWwKkGmwhsA • https://www.youtube.com/watch?v=6ldtdWjDwes • https://www.youtube.com/watch?v=ZZ-XUG46VDI • https://www.youtube.com/watch?v=mkPawVQfZko

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