Chapter 1: Introduction to genetics

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Chapter 1 Introduction to genetics
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A brief introduction about myself

• 1987.9-1991.7
• Southwest Teachers University, Bachelor
• 1991.9-1997.7
• Sichuan University, Master, Ph D
• 1997.7-now Hubei University
• 2003.4-2004.3
• Swedish University of Agricultural Sciences

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Why do I want to teach in English?

• China is becoming more and more international
• All the best scientific journals are in English
• We have to be able to communicate in English
• What is the problem with our learning English

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What should we achieve?

• Communicate in English
• Read English literatures
• Know the basics of genetics
• Know how to work with science

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Science and Civilisation in China
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The question of Joseph Needham

• Why did modern science originate in western
  countries instead of China?
• Why cant we native Chinese scientists get Nobel
  prize?
• Why could Mendel discover the two basic genetic
  laws?
• What should we learn from Mendel, Morgan, Watson,
  Crick, Etc.?

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How will we go ahead?

• I teach a few chapters
• You teach the other chapters
• We discuss

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1.1 What is genetics?

• genetics The branch of biology that deals with
  heredity variation.
• heredity the similarity between progenitors and
  progeny
• Variation difference between generations and
  individuals of the same species

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1.2 History of genetics

• Prehistoric times domesticated animals and
  cultivated plants
• Our ancient ancestors learned that desirable
  and undesirable traits are passed to successive
  generations and that by influencing their
  breeding, many desirable varieties of animals and
  plants could be obtained.

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The Greek influence Hipocrates

• Hipocrates argued that male semen is formed in
  numerous parts of the body and is transported
  through blood vessels to the testicles.
• Pangenesis Particles or fluids from various
  parts of the body accumulate in germ cells, and
  are transmitted to the offspring.
• This theory believed in the passing on of
  characters acquired during lifetime of the
  individual.

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Hipocrates
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The Greek influence Aristotle

• Aristotle proposed that male semen was formed
  from blood rather than from each organ, and that
  its generative power reside in a vital heat that
  it contained.

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Aristotle
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Before Mendel Preformation

• Leeuwenhoek and his students believed they saw
  through their microscope small encapsulated
  creatures within the sperms.
• Bonnet (1720-1793) An embryo contained a smaller
  embryo, which contain another smaller embryo, so
  on.

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Before Mendel epigenesis

• Wolff suggested that organisms develop by
  epigenesis, i.e., development starts from
  undifferentiated fertilized egg and proceeds
  through successive formation and addition of new
  parts which did not exist there before.

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Doctrine of use and disuse

• Lamark (1744-1829) proposed that organisms
  acquire or lose characteristics that then became
  inheritable.

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Lamark

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Pangenesis and the inheritance of acquired
characteristics

• Charles Darwin described the physical units
  representing each body part that were gathered by
  the blood into the semen. He felt these units
  determined the nature or form of each body part
  and they could respond in an adaptive way to the
  external environment. Once altered, such changes
  would be passed onto offspring, allowing for the
  inheritance of acquired characteristics.

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Charles Darwin
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August Weismann and Francis Galton

• Weismann cut off the the tails of mice for 22
  generations, yet the newborn displayed tails just
  as long as those of their ancestors.
• Galton performed blood transfusions among
  different breeds of rabbits, without any
  hereditary consequences.

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August Weismann
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Francis Galton
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Gregor Mendel
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Gregor Mendel

• Mendel published his classic paper in 1866. In
  this paper Mendel demonstrated a number of
  statistical patterns underlying inheritance and
  developed a theory involving hereditary factors
  in the germ cells to explain these patterns.

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After Mendel

• 1900, De Vries,Correns and Tschermak rediscovered
  Mendels paper
• 1903, Sutton and Boveri, Chromosomal theory of
  inheritance
• 1909, Johansen coined gene for genetic factor
• Around 1910, Morgan and his students
  Sturtevant,Bridges and Muller gene theory

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Morgan TH
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After Mendel

• 1927, Muller and Stadler irradiation genetics
• 1940, McClintock transposon
• 1941, Beadle and Tatum one gene for one enzyme
• Avery (1944), Hershey (1952) genetic material is
  DNA instead of protein
• 1953, Waston and Crick double helix model

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Barbara McClintock

• Discovered transposon
• in 1940 and was
• awarded Nobel Prize
• in 1983.

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Watson and Crick



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After Mendel

• 1973, genetic engineering.
• 1990, Human Genome Project?genomics.
• 1997, Clone of Dolly.
• Functional genomics Protemics

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Genetics and Agriculture

• Hybrid vigor
• Disease resistance
• Pest resistance
• Herbicide resistance
• Select for various mutants
• Utilization of bacteria to produce useful
  industrial materials

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Yuan Longping

• The father of hybrid rice

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Fu Tingdong

• Found the first useful
• male sterile line--
• CMS Polima in
• Rapeseed.

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Genetics and Medicine

• Understanding the genetic basis of many disease
  including cancer.
• Development of new medicines through genetic
  engineering.

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Genetics and environment protection

• Utilization of genetically modified plants to
  clean heavy metals.
• Utilization of genetically modified bacteria to
  clean the water.
• etc.