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

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 1 The early days of DNA,Genes & Chromosomes
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Timeline of DNA 1865: Gregor Mendel discovers via breeding experiments with peas that traits are inherited based on specific laws (later termed “Mendel's laws”) 1869 : Friedrich Miescher isolates “nuclein” (DNA) for the first 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 of 1909) are located on chromosomes. 1909 : Wilhelm Johannsen uses the word “gene” to describe units of heredity. 1910 : Thomas H. Morgan uses fruit flies (Drosophila) to study heredity, finds first mutant fly and demonstrates that genes are on chromosomes. 1913 : Alfred Sturtevant and Thomas Hunt Morgan produce the first genetic linkage map (for the fruit fly Drosophila ). 1928 : Frederick Griffith postulates that a “transforming principle” permits properties from one type of bacteria (heat-inactivated virulent Streptococcus pneumoniae) to be transferred to another (live nonvirulent Streptococcus pneumoniae). 1944 : Oswald T. Avery, Colin MacLeod, and Maclyn McCarty demonstrate that Griffith's “transforming principle” is not a protein, but rather DNA, suggesting that DNA may function as the genetic material. 1949-50 : Erwin Chargaff finds that the DNA base composition varies between species but determines that within a species the bases in DNA are always present in fixed ratios: the same number of A's as T's and the same number of C's as G's. 1950: Barbara McClintok reported results of maize experiments indicating moveable genes, now called transposable elements 1952 : Alfred Hershey and Martha Chase use viruses (bacteriophage T2) to confirm DNA as the genetic material by demonstrating that during infection viral DNA enters the bacteria while the viral proteins do not and that this DNA can be found 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 : James Watson & Francis Crick discover the molecular structure of DNA: a double helix in which A always pairs with T, and C with G. 1956 : Arthur Kornberg discovers DNA polymerase, an enzyme that replicates DNA. 1957 : Francis Crick proposes the “central dogma” (information in the DNA is translated into proteins through RNA) and speculates that three bases in the DNA always specify one amino acid in a protein. 1958 : Matthew Meselson and Franklin Stahl describe how DNA replicates (semiconservative replication). 1961-66 : Robert W. Holley, Har Gobind Khorana, Heinrich Matthaei, Marshall W. Nirenberg, and colleagues crack the genetic code.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern