Lec1 - Lecture 1 The early days of DNA,Genes Chromosomes...

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Lecture 1 The early days of DNA,Genes & Chromosomes
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Timeline of DNA 1865: Gregor Mendel discovers via breeding experiments with peas that traits are inherited based on specifc laws (later termed “Mendel's laws”) 1869 : Friedrich Miescher isolates “nuclein” (DNA) ±or the frst time. 1882 : Walther Flemming describes chromosomes and examines their behavior during cell division. 1889 : Richard Altmann renames “nuclein” to “nucleic acid”. 1900 : Carl Correns, Hugo de Vries, and Erich von Tschermak rediscover Mendel's Laws. 1902 : Theodor Boveri and Walter Sutton postulate that the heredity units (called “genes”as o± 1909) are located on chromosomes. 1909 : Wilhelm Johannsen uses the word “gene” to describe units o± heredity. 1910 : Thomas H. Morgan uses ±ruit ²ies (Drosophila) to study heredity, fnds frst mutant ²y and demonstrates that genes are on chromosomes. 1913 : Al±red Sturtevant and Thomas Hunt Morgan produce the frst genetic linkage map (±or the ±ruit ²y Drosophila ). 1928 : Frederick Gri±fth postulates that a “trans±orming principle” permits properties ±rom one type o± bacteria (heat-inactivated virulent Streptococcus pneumoniae) to be trans±erred to another (live nonvirulent Streptococcus pneumoniae). 1944 : Oswald T. Avery, Colin MacLeod, and Maclyn McCarty demonstrate that Gri±fth's “trans±orming principle” is not a protein, but rather DNA, suggesting that DNA may ±unction as the genetic material. 1949-50 : Erwin Charga±± fnds that the DNA base composition varies between species but determines that within a species the bases in DNA are always present in fxed ratios: the same number o± A's as T's and the same number o± C's as G's. 1950: Barbara McClintok reported results o± maize experiments indicating moveable genes, now called transposable elements 1952 : Al±red Hershey and Martha Chase use viruses (bacteriophage T2) to confrm DNA as the genetic material by demonstrating that during in±ection viral DNA enters the bacteria while the viral proteins do not and that this DNA can be ±ound in progeny virus particles. 1953 : Rosalind Franklin and Maurice Wilkins use X-ray analyses to demonstrate that DNA has a regularly repeating helical structure. 1953 1956 : Arthur Kornberg discovers DNA polymerase, an enzyme that replicates DNA. 1957 : Francis Crick proposes the “central dogma” (in±ormation in the DNA is translated into proteins through RNA) and speculates that three bases in the DNA always speci±y one amino acid in a protein. 1958 : Matthew Meselson and Franklin Stahl describe how DNA replicates (semiconservative replication). 1961-66
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Lec1 - Lecture 1 The early days of DNA,Genes Chromosomes...

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