Genetics: Historical Perspectiveclasspages.warnerpacific.edu/bdupriest/BIO 250/Lecture 1...
Transcript of Genetics: Historical Perspectiveclasspages.warnerpacific.edu/bdupriest/BIO 250/Lecture 1...
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Genetics:
Historical Perspective
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Ancient History
8000-1000 BC
Domestication & selective breeding
Cattle
Horses
Dogs
800 BC
Artificial Pollination
Date palms
Maize
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Heredity
What is actually being transmitted, and how
does it happen?
What is the source of the physical substance that
gives rise to offspring?
What is the nature of the generative force that directs
development of that physical substance?
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Ancient History
500-400 BC
Hippocrates
On the Seed
Active Humors
Drawn to semen from body
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Ancient History
384-322 BC
Aristotle
“Vital Heat” in semen could produce offspring of the
same form
Cooked & shaped menstrual blood
The School of Athens, Raphael
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Medieval History
1600s AD
Preformation
Sperm contained complete miniature adults
Homunculus
William Shakespeare
https://www.youtube.com/watch?v=PgSJBAbwv58
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Victorian Era
1830
Cell theory – Schleiden & Schwann
All living organisms are composed of basic structural
units called cells
First Wagon Train over Oregon trail, 1830, William Henry Jackson
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Victorian Era
1859
On the Origin of Species –
Charles Darwin
Natural Selection
Competition for survival
Organisms w/ traits that are beneficial show increased
chance for survival
If these beneficial traits are heritable, accumulation of these
traits may lead to development of new species over time
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Victorian Era
1866
Gregor Mendel
Statistical patterns of inheritance
1869
Friedrich Miescher
Discovered DNA
1879
Walther Flemming
Discovered chromosomes
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20th Century
1900
Thomas Morgan
Chromosomal Theory of Inheritance:
Heredity is dependent upon the information contained in
chromosomes, which are contributed by the gametes of
each parent
1920s
Microscopy showed DNA is in chromosomes
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20th Century
1941
Beadle & Tatum
One gene, one enzyme hypothesis
1944
Avery, McLeod, and McCarty
DNA is the genetic material – first evidence
1952
Hershey & Chase
DNA is the genetic material – definitive proof
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Hershey-Chase Experiment
DNA, not protein, is responsible for
bacteriophage activity in bacterial cells
Phage DNA enters bacterial host cell; protein coat
remains outside
Phage DNA directs reproduction of the virus in
infected bacterial cells
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20th Century
1953
Watson & Crick
Double helix structure of DNA
1955
Tjio
Human chromosome number identified: 23 pairs
1966
Nirenberg, Khorana, Ochoa
Identification of the genetic code
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20th Century
1970s
Recombinant DNA technology & gene sequencing
techniques developed
1990
Human Genome Project launched
1994
First genetically modified
food approved for sale
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20th Century
1995
First complete genome sequenced
Haemophilus influenzae
1996
First mammal cloned – Dolly the sheep
1999
First human chromosome sequenced (#22)
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21st Century
2003
Human genome sequence completed
Craig Venter – Celera Genomics
Francis Collins – Nat’l Human Genome Research Institute
3 billion base pairs
~30,000 genes
http://en.wikipedia.org/wiki/File:Craigventer2.jpghttp://en.wikipedia.org/wiki/File:Francis_Collins_official_portrait.jpg
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21st Century
Beyond genetics: Genomics
Personalized medicine
Model organisms are used to study genetics