Transcript History of Genetics

REVIEW
DNA
• ___________ contains all the genetic
instructions to create all the cells in
your body.
• What Does DNA stand For?
Deoxyribonucleic Acid
GENE -part of a DNA molecule
• ________
that determines the inherited trait.
• Chromosome
____________ - condensed DNA,
acts as a storage unit.
REVIEW
• Where in the cell are chromosomes
located? Nucleus
• How many pairs of chromosomes do
we as Humans have?
23 pairs of Chromosomes
• How many chromosomes do you get
from each parent?
23 chromosomes from each parent
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History of Genetics
People have known about inheritance for a
long time.
- children resemble their parents
- selective breeding of dogs (for breeds)
and cattle (best milk or meat)
IMPORTANT Discoveries
Three major events in the mid-1800’s led
directly to the development of modern genetics:
1) Charles Darwin
2) Gregor Mendel
3) Friedrich Miescher
IMPORTANT Discoveries
• Three major events in the mid-1800’s led directly
to the development of modern genetics.
• 1859: Charles Darwin publishes The Origin of
Species, which describes the theory of evolution
by natural selection. This theory requires
heredity to work.
• 1866: Gregor Mendel publishes Experiments in
Plant Hybridization, which lays out the basic
theory of genetics. (Law of Inheritance)
• 1871: Friedrich Miescher isolates “nucleic acid”
from bread mold.
Major Events in the 20th Century
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• 1910: Thomas Hunt Morgan: proved that genes are
located on the chromosome
• 1941: Beadle and Tatum - show how genes direct the
synthesis of enzymes that control metabolic processes
“1 gene = 1 enzyme”
• 1952: Hershey and Chase - conducted experiments
which helped to confirm that DNA was the genetic
material that transported traits.
More 20th Century Events
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• 1953: Watson and Crick - determine the structure of the
DNA molecule, which leads directly to knowledge of how
it replicates
• 1966: Marshall Nirenberg solves the genetic code,
showing that 3 DNA bases in a row code for one amino
acid.
• 2001: Sequence of the entire human genome is
announced.
Summarizing What we’ve learnt
HOMEWORK
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• Complete Worksheet for next lesson
First ½ is the most important