telo and metaphase
Genetics History
©David B. Fankhauser, Ph.D.
Professor of Biology and Chemistry
University of Cincinnati Clermont College,
Batavia OH 45103
 PCR D1S80 banding
Anton Van Leeuwenhoek
using his improved simple
microscope.

This page has been accessed Counter times since 4 January 2009.
rvsd 27 Sept '96, 3 Jan 00, 3 Jan 01, 6 Jan 03, 6 Jan 04, 9 Jan 08, 4 January 2009
Mendel's Garden where he
performed his classic genetic
crosses of Pisum sativum

For excellent overview, see BKH, 6th, World of the Cell, pp 510-518 and p 10


Early practical Genetics: 10,000 yrs ago with domestication (selective breeding of animals with desirable traits)


Two critical observations must be explained:

              Why do offspring look like their parents:                         = HEREDITY

              Why do offspring look different from their parents:       = VARIATION

Regnier de Graaf

1640

observed Graafian follicle, spawned those who thought maternal inheritance

Leeuwenhoek
second image

1644

Improved simple microscope, saw semen, names animalcules, spawned those who thought they saw human form in sperm head, paternal inheritance (maternal prenatal influence).  Here are photographs of one of Leewuenhoek's original microscopes,  another.

 

19th cent

thought blending of traits: Snapdragons: red x white yields pink, skin color

Gregor Mendel (Ignored for 35 yrs)

1866

studied peas at an abby in Brno, Czeckoslovakia.  Proposed 

FIRST LAW:           1. Each trait due to a pair of hereditary factors which

2. segregate during gametogenesis

SECOND LAW:      3. Multiple sets of hereditary factors assort independently

 

 

DNA IS GENETIC MATERIAL:

Friedrich Miescher (75 yrs ahead of time)

1869

Swiss physician, alkali extraction of “nuclein” from human pus from surgical bandages and salmon sperm (90% nucleus). Thought it was genetic material.

Walther Flemming

1880

observed thread-like structures in dividing cells, termed chromosomes, process mitosis.

Eduard Zacharias

1880s

botanist, showed that extraction of DNA from cells caused staining of chromosomes to disappear, inferred that DNA is genetic material.

Wilhelm Roux

1883

suggested that chromosomes might carry genetic information

Correns,

von Tschermak,

de Vries

1900

three independently and simultaneously rediscovered Mendel's work, understood its significance

Walter Sutton

1903

proposed chromosome theory of heredity, linking Flemming's threads with Mendel's factors

Thomas H. Morgan

1910-

1920

Morgan (and his grad students at Columbia) used Drosophila melanogaster to show Sutton correct.                                                                   [END OF FIRST DAY, 1/3/05, 1/4/06]

Robert Feulgen

1914

developed a stain preferential for DNA, showed component in chromosomes. But most thought not the genetic material because:
1) different degrees of staining in dif. cells

2) only four bases

Fredrick Griffith

1928

Demonstrated transformation of rough Pneumococcus to smooth in vivo.  Rough and smooth strains of Pneumococcus

Avery, MacLeod and McCarty

1944

 showed DNA could transform bacteria, “transforming principle” is gen. mat.

Beadle and Tatum

1940s

formulated “one gene-one enzyme” hypothesis using mutants of Neurospora crassa

Hershey and Chase

1952

Labeled phage with P-32 or S-35, showed DNA injected, not protein.

Rosalind Franklin,

1953

Working with Maurice Wilkins, she got an excellent Xray diffraction picture of DNA.  It indicated that DNA was a helix, with particular spacing of units

 James Watson and Francis Crick

 

Using Franklin's date (without attribution), elucidated the structure of DNA.  Complimentary nature of base pairing. Rotating DNA (slow).  Rotating DNA.