For lecture only BC Yang

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• ???????

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• In 1833, even before Schleiden and Schwann had
  presented their cell theory, Robert Brown had
  described an ovoid in the cell as the "nucleus",
  and Dumortier and von Mohl had discovered binary
  fission of the nucleus and cell. Remak gave the
  first descriptions of the changes that occur in
  the nucleus, and Purkinje underlined its
  importance and the requirement for this organelle
  throughout the life of a cell.

???? http//www.zoo.uni-heidelberg.de/lankenau/Te
aching/Vorlesung/stunde16/stunde_16.htm
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Francis Galton (1822-1911) offers a statistical
approach to understanding inheritance.
??????

• Employing impressionistic data about talented
  individuals and their families, Galton proposed
  the "law of ancestral inheritance" in 1876.
  Revised several times over the next two decades,
  Galton's basic conception was that, on average,
  each parent provides offspring with one quarter
  of inherited traits, while grandparents
  contribute the rest. Francis Galton The "law of
  ancestral heredity," as it turned out, was
  mistaken. Although he was interested in
  individual variations, Galton's mathematical
  methods treated them as "errors." In Gregor
  Mendel's more carefully conceived experiments
  with culinary peas, variations represented the
  expression of discrete alternative factors or (as
  we would say today) genes. Galton, in his
  personal correspondence with Darwin, came close
  to this conception, but never proceeded to a
  testable formulation.

http//www.genomenewsnetwork.org/timeline/1876_Gal
ton.shtml
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• 1866, Mendel published his lecture, a work that
  was to establish him as the father of genetics.
  
• 1869 Johann Friedrich Miescher (nuclein)
• 1873 Anton Schneider (meiosis)
• 1879 Walther Flemming (chromaton, mitosis)
• 1888 Wilhelm von Waldeyer-Hartz, (term
  chromosome)
• 1902 Walter Stanborough Sutton. (chromosomes
  carry the units of inheritance)
• 1904 Theodor Boveri (correlation between Mendel's
  factors and chromosomes )
• 1904 William Bateson (genetics)
• 1909 Wilhelm Johannasen (gene)

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DNA to chromosome to DNA

• 1869 Johann Friedrich Miescher identifies a
  weakly acidic substance of unknown function in
  the nuclei of human white blood cells. This
  substance will later be called deoxyribonucleic
  acid, or DNA.
• 1924 Microscope studies using stains for DNA and
  protein show that both substances are present in
  chromosomes.
• 1928 Franklin Griffith, a British medical
  officer, discovers that genetic information can
  be transferred from heat-killed bacteria cells to
  live ones. This phenomenon, called
  transformation, provides the first evidence that
  the genetic material is a heat-stable chemical.
• 1944 Oswald Avery, Maclyn McCarty, and Colin
  MacLeod, identify Griffith's transforming agent
  as DNA.

Good simple reference to read
http//www.csuchico.edu/anth/CASP/Carmosino_P.html
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• It was while working on pus cells at Tübingen in
  1869 that Miescher made his fundamental
  discovery. It was thought that such cells were
  made largely of protein, but Miescher noted the
  presence of something that "cannot belong among
  any of the protein substances known hitherto."
• He showed that the new substance was derived from
  the nucleus of the cell alone and consequently
  named it 'nuclein'.
• Miescher was soon able to show that nuclein could
  be obtained from many other cells and was unusual
  in containing phosphorus in addition to the usual
  ingredients of organic molecules - carbon,
  oxygen, nitrogen, and hydrogen. It was not until
  1871 that Miescher's paper, delayed by
  Hoppe-Seyler (who wanted to confirm the results),
  was published.

Miescher, Johann Friedrich II1844-1895 
Switzerlander
http//www.laskerfoundation.org/news/gnn/timeline/
1869a.html
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1873 and after

• The discovery of chromosomes cannot be pinpointed
  to a single person. It was a consequence of the
  growing interest in the division processes of the
  fertilized egg.
• Scientists on cell division Anton Schneider,
  Eduard Strasburger, Otto Bütschli, Edouard van
  Beneden, Leopold Auerbach, Hermann Fol, Walther
  Flemming.

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• One of the first discoverers was the zoologist
  Anton Schneider in 1873 who showed by adding
  acetic acid to fertilized eggs of the plathelmith
  Mesostomum Ehrenbergii that the nucleus
  disappears and that it changes to a bulk of thin
  threads subsequently becoming thicker and
  differentiating along an axis through the cell.
  The fibers finally separate and can be followed
  into each of the new cells formed from each other
  by lacing in from the edges of the original cell.
  
• Schneider remarked "These (observations) for the
  first time show us how intricate the
  metamorphosis of the nucleus (the germ pustule)
  is during cell division."

Friedlich Anton Schneider, 1873 Untersuchung uber
Platyhelminthen in Oberhessischen Gesellschagt
fur Natur-und Heilkinden 1469-140.
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Walther Flemming1843 - 1905

• 1879 he described and named "chromaton",
  "mitosis" and "spireme", made the first accurate
  counts of chromosome numbers and figured the
  longitudinal splitting of chromosomes.

http//www.nature.com/cgi-taf/DynaPage.taf?file/n
rm/journal/v2/n1/full/nrm0101_072a_r.html
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• Flemming observed for the first time that the
  chromosomes during cell division became split
  along their longitudinal axis, now known to
  consist of chromatids, and in 1880 he formulated
  the sentence "Omnis nucleus e nucleo".
• All nuclei come from nuclei

(1863), omnis cellula e cellula
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The term chromosome, the name was introduced in
1888 by von Waldeyer, and the process of cell
division were now well established.

• Waldeyer-Hartz, Wilhelm von (German). 1888. Über
  Karyokinese und ihre Beziehungen zu den
  Befruchtungsvorgängen. Archiv für mikroskopische
  Anatomie und Entwicklungsmechanik 32 1-122

1836-1921
http//vlp.mpiwg-berlin.mpg.de/people/data/per357.
html
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Walter Stanborough Sutton.

• He was the U.S. geneticist (and also surgeon) who
  provided the first conclusive evidence that
  chromosomes carry the units of inheritance and
  occur in distinct pairs.
• The two papers (Sutton, 1902, 1903) written as a
  graduate student under E. B. Wilson at Columbia
  University formulated the concept that
  chromosomes carried the units of heredity and
  explained Mendel's laws.

1877-1916
http//www.kumc.edu/research/medicine/anatomy/sutt
on/surgical_career.html
http//post.queensu.ca/forsdyke/guyer.htmChromos
omes20in20Heredity
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I believe this is what Sutton has seen during his
study at Columbia University (BC, 2004)

• While he was working as a graduate student at
  Columbia University, studying grasshopper cells,
  Sutton observed that chromosomes occurred in
  distinct pairs, and that during meiosis, the
  chromosome pairs split, and each chromosome goes
  to its own cell. Sutton announced this discovery
  in his 1902 paper On the Morphology of the
  Chromosome Group in Brachyotola.

http//www.kumc.edu/research/medicine/anatomy/sutt
on/surgical_career.html
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• On pages 24-39 of Biological Bulletin, dated
  October 17th 1902, Sutton noted Montgomery's
  "suggestion that maternal chromosomes unite with
  paternal ones in synapsis" and briefly called
  "attention to the probability that the
  association of paternal and maternal chromosomes
  in pairs and their subsequent separation during
  the reducing division ... may constitute the
  physical basis of the Mendelian law of
  heredity." 
• This was amplified in the 1903 paper (Biological
  Bulletin 1903 4, 231-251) which, summarizing the
  above work and that of Montgomery, Bateson and
  Saunders, Bovari, McClung, and himself, set out
  quite clearly the idea of the random assortment
  of paternal and maternal chromosomes in germ
  cells where meiosis is normal (no hybrid
  sterility).

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Theodor Boveri (1862-1915)

• He saw that as egg cells matured, there comes a
  point where chromosome numbers are reduced in
  half. Boveri was one of the first to see evidence
  of the process of meiosis. (In the late 1880's
  and early 1890's)
• When Mendel's laws were rediscovered in 1900,
  Boveri recognized the correlation between
  Mendel's factors and the cytology work being done
  on chromosomes (1904?).

Some one had already improved the staining
technique for chromosomes http//www.dnaftb.org/d
naftb/concept_8/con8bio.html
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• Theodor Boveri, making use of the ideas from Carl
  Rabl put forward the hypothesis of the constancy
  of the amount of chromosomes and of their
  continuity during the Interphase stages of the
  nucleus (1887-1888). In 1904 Boveri already even
  thought it might be possible that the pairing of
  chromosomes would result in an exchange of
  genetic substance.

??????
Bamburg, Deutshland
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William Bateson (1861-1926)
William Bateson describes gene linkage, showing
that more than one gene may be required for a
particular characteristic or trait (1904). A
hereditary factor like, for example, the shape of
the seed, the colour of the cotyledons or the
colour of the seed shell shall be called a gene
(following a suggestion of BATESON made in 1905).
http//post.queensu.ca/forsdyke/bateson1.htm
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http//www.dnaftb.org/dnaftb/concept_5/con5gallery
.html
First page of a 1905 letter written by William
Bateson, first Director of the John Innes
Institute, to Adam Sedgewick, Cambridge
professor. Bateson coined the term "genetics" in
this letter. he felt the need for a new term to
describe the study of heredity and inherited
variations. But the term didnt start spreading
until Wilhelm Johannsen suggested that the
Mendelian factors of inheritance be called genes.
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Wilhelm Johannasen
1857-1927

• Danish botanist Wilhelm Johannsen coined the word
  gene (1909) to describe the Mendelian units of
  heredity.
• He also made the distinction between the outward
  appearance of an individual (phenotype) and its
  genetic traits (genotype).
• The proposed word traced from the Greek word
  genos, meaning "birth". The word spawned others,
  like genome.

http//www.genome.gov/Pages/Education/Kit/main.cfm
?pageid24
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Are you satisfied to accept the Mendels laws?
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