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1655 - Robert Hooke (1635-1703) of Britain
designed his own microscope and discovered matter
made up of what he called cells.
1759 - C.F. Wolff (1733-1794)
of Germany proposed a general cell theory.
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1838 - Matthias J. Schleiden (1804-1881)
of Germany published a cell theory as applied
to plants.
1839 - Theodor Schwann (1810-1882)
of Germany published cell theory as applied
to animals.
1857 - Gregor
Johann Mendel (1822-1844), an Austrian
monk, began experiments with pea plants. He
later became known as the "father of
genetics."
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1859 - English biologist Charles
Darwin (1809-1882) published “Origin
of Species,” explaining units of heredity
and variations in species.
1865 - Mendel announced his theories
of heredity, known as Mendel’s Laws.
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1869 - Sir Francis Galton
(1822-1911) of Britain published his book, Hereditary
Genius, claiming that heredity alone is responsible
for a person’s character traits.
1882 - German biologist Walther
Fleming (1843-1905) used dyes to stain cells; he
discovered rods he called “chromosomes.”
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1886 - Dutch botanist Hugo
de Vries (1848-1935) created term “mutation”
while experimenting with primroses.
1887 - Belgian biologist Edouard van
Beneden (1846-1910) discovered that all organisms
of the same species have the same number of
chromosomes.
1892 - August
Weismann (1834-1914) published
an essay on heredity. He proposed heredity
was transmitted by a substance with a “chemical
and molecular constitution”--he greatly influenced
subsequent biologists.
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1900 - De Vries published
a paper that included the laws of inheritance as
do two others: German botanist Karl Erich Correns
(1864-1933) and Austrian botanist Erich Tschermak
von Seysenegg (1871-1962).
1901 - De Vries published a
paper on mutations.
1902 - American biologist Walter
Stanborough Sutton (1877-1916) demonstrated that
chromosomes exist in pairs that are structurally
similar.
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1903 - Sutton proved that sperm and
egg cells have one of each pair of chromosomes.
1908 - American biologist Thomas
Hunt Morgan (1866-1945) with Alfred
H. Sturtevant of the U.S. showed that genes
were located on chromosomes; he experimented
with Drosophelia (fruit flies) to investigate
sex chromosomes, and discovered X and Y chromosomes,
sex-linked traits, and crossing-over.
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1909 - Danish botanist Wilhelm
Ludvig Johannsen (1857-1927) proposed that each
portion of a chromosome that controls a phenotype
be called a “gene” (Greek: “to give birth to”).
1913 - Alfred Henry Sturtevant
(1891-1970) began constructing a chromosome map
for Drosophelia (it was completed in 1951 for all
four Drosophelia chromosomes).
1919 - Hermann Joseph Muller
(1890-1976) of the U.S. experimented with Drosophelia
to create more mutant flies.
1941 - George W. Beadle (1903-1989)
of the U.S. and Edward L. Tatum (1909-1975) of the
U.S. discovered that genes control the production
of enzymes.
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1944 - Oswald T. Avery (1877-1955)
of the U.S. announced that DNA alone is the
substance responsible for heredity.
1952 - Francis
H. C. Crick (1916- ) of Britain
and James D. Watson
(1928- ) of the U.S. made a model of the DNA
molecule and proved that genes determine heredity.
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| 1950’s - Maurice
Wilkins (1916- ), Rosalind
Franklin (1920-1957), Crick and Watson
discover chemical structure of DNA, starting
a new branch of science--molecular biology. |
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1957 - Arthur Kornberg (1918-
) of the U.S. produced DNA in a test tube.
1966 - The Genetic code was
discovered; scientists are now able to predict characteristics
by studying DNA. This leads to genetic engineering,
genetic counseling.
1972 - Paul Berg (1926- ) of
the U.S. produced the first recombinant DNA molecule.
1982 - The first recombinant
DNA drug approved by the FDA--genetically engineered
insulin for diabetics.
1983 - Barbara McClintock (1902-1992)
of the U.S. was awarded the Nobel Prize for her
discovery that genes are able to change position
on chromosomes.
1988 - An international team
of scientists began the project to map the human
genome.
The Late 1980’s - The first
crime conviction based on DNA fingerprinting, in
Portland Oregon.
1990 - Gene therapy was used
on patients for the first time.
1994 - The FDA approved the
first genetically engineered food--FlavrSavr tomatoes
engineered for better flavor and shelf life.
1995 - DNA testing in forensics
cases gains fame in the O.J. Simpson trial.
1997 - Dolly the Sheep--the
first adult animal clone.
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