Leaf 41 . gif
Did you hear about the guy who said it couldn't be done?
Well, he got run over by the guy doin' it!


1. Introduction/personal background

2. A Brief History of Genetics

3. Discussion about the course - policy, attendance, exams, etc……

CLONED Ginger-bread people bar

Mary had a little lamb,
its fleece was slightly grey,
It didn't have a father,
just some borrowed DNA.
It sort of had a mother,
though the ovum was on loan,
It was not so much a lambkin,
as a little lamby clone.
And soon it had a fellow clone,
and soon it had some more.
They followed her to school one day,
all cramming through the door.
It made the children laugh and sing,
the teachers found it droll,
There were too many lamby clones,
for Mary to control.
No other could control the sheep,
since their programs didn't vary,
So the scientists resolved it all,
by simply cloning Mary.
But now they feel quite sheepish,
those scientists unwary,
One problem solved,
but what to do,
with Mary, Mary, Mary...

Cloned little bunny rabbits

Cloning of Dolly the Sheep

Gregor Mendel

A Brief History of Genetics
(esp. DNA)
(G.J. Mulder isolates protein)
Schleider and Schwann propose "cell theory"
Darwin’s Origin of the Species (first edition)
Gregor Mendel describes unit of heredity
Haeckel postulates nucleus of cells contain hereditary information
Friedrich Miescher isolates "nuclein" (DNA) from trout from the Rhine, in Switzerland (Hoppe-Seyler repeats the work of his student, in Tübingen)
Discovery of purines (by A. Kossel) Discovery of Chromosomes (by Walther Flemming)  
    Charles Darwin dies
Altmann names "nucleic acids" W. Waldeyer coins name for chromosomes  
(Emil Fisher postulates chemical crosslinks of amino acids in proteins) de Vries, Correns, and Tschermak
each independtly "rediscovered" Mendel’s hereditary units

Flower 02 bar

Darwin . jpg
    With the rediscovery of Mendel's laws, a physical basis for inheritance was now avaliable. This allowed for the fusion of the fields of genetics and evolution. R.A. Fisher (in the U.K.) and TheodorsiusDobzhansky (in the U.S.) were amongst the earliest proponents of this synthesis.


Leaf 42 . bar

(esp. DNA)
(& Evolution)
two purines (A & G) found "in equamolar amounts" in DNA Walter Sutton proposes that chromosomes contain genetic material
All 4 bases in DNA now characterised, (incl. T & C) in roughly equal amounts T.H. Morgan proposes that genes can mutate (somehow) (from work with Drosophila)
"enzymes" found to be made from proteins Archibold Garrod proposes chromosomes affects enzymes (somehow)
Phosphate "backbone" proposed to connect DNA bases together Morgan publishes book describing 85 different mutations in Drosophila
ribose sugar associated with DNA characterised Muller discovers x-rays induce mutations in chromosomes
Nucleic Acids book published by Levine;

Griffith discovers "transformation"

Barbara McClintock shows recombination in corn (links theoretical gene to chromosome)
Griffith and lab co-worker are killed in their lab (in London) when it is bombed Beadle and Tatum propose "one gene, one enzyme" hypothesis
Avery, MacLeod, McArty show DNA is "transforming" agent (e.g., genetic material).  

1951 (Linus Pauling discovers protein a-helix)

1952 Alfred Hershey & Martha Chase demonstrate that DNA
contains genetic material

1953 Postulation of a complimentary, double helical structure
for DNA (by Watson and Crick).

1955 Chargaff & Davidson publish exhaustive set of three volumes
on "The Nucleic Acids", describing in great detail their physical
properties and characterisation.

1956 Genetic experiments support hypothesis that genetic
messages of DNA are conveyed by its sequence of bp.

1958 Messelson and Stahl demostrate that DNA replicates semi-
Isolation of the first enzyme (DNA polymerase I)

1959 Discovery of RNA polymerase.

1960 Discovery of messenger RNA.

1961 The triplet nature of the genetic code is discovered
Monad and Jacob propose operon model of gene regulation

1965 Appreciation that genes conveying antibiotic resistence
in bacteria are often carried on small bits of extrachoromo-
somal DNA (plasmids).

1966 Establishment of complete genetic code.

1967 Isolation of the enzyme DNA ligase

1970 Isolation of the first restriction enzyme
Temin and Baltimore report the discovery of reverse
transcriptase in retroviruses.

1972 Use of ligase to link together restriction fragments.
First recombinant molecules generated

1973 Eukaryotic genes are cloned in bacterial plasmids

1974 Call for world-wide moratorium on certain classes of
recombinant DNA experiments.

1976 Retroviral oncogenes are identified as the causative agents
of transformation

1977 DNA sequencing becomes possible.
Interrupted genes are discovered and splicing of their
transcripts is inferred.

1978 Production of first human hormone (somatostatin)
using recombinant DNA methods.

1979 Cellular oncogenes are discovered by transfection.

1981 Catalytic activity of RNA is discovered.
Transgenic mice and flies are obtained by introducing
new DNA into the germ line.

1983 First version of "GenBank" created for storage of DNA

1986 proposal of Intramolecular Triplex structure for certain
purine rich DNA sequences.

1989 Polymerase Chain Reaction (PCR) technique first used.

1995 First BACTERIAL genomes completely sequenced.
(Haemophilus influenza and Mycoplasma genetilium)

1996 genome of first EUKARYOTE completely sequenced.
(Saccharomyces cerevisiae, 13,000,000 bp on 16
genome of first Archaebacteria completely sequenced.
(Methanococcus jannaschii )
genome of first cyanobacteria completely sequenced.
(Synechocystis sp., PCC 6803)

1997 Dolly the Sheep cloned (and Molly, and Polly....)
E.coli genome sequenced (finally!).

1998 Doctor in Chicago announces he will clone a human "within
the next two years".
Dolly the sheep is pregnant (!)

Cloned Lion

Figure 1_03 (Griffiths)

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