Golden Rice or Frankenfood

1
Golden Riceor Frankenfood?

• Scientists transferred daffodil genes into rice
• Rice with beta-carotene may help prevent vitamin
  A deficiencies
• Opponents fear unforeseen consequences of
  creating genetically modified organisms

2
Genetic Changes

• Humans have changed the genetics of other species
  for thousands of years
• Artificial selection of plants and animals
• Natural processes also at work
• Mutation, crossing over

3
Genetic Engineering

• Genes are isolated, modified, and inserted into
  an organism
• Made possible by recombinant DNA technology
• Cut up DNA and recombine pieces
• Amplify modified pieces

4
Discovery of Restriction Enzymes

• Hamilton Smith studied how bacterium Haemophilus
  influenzae cut invading viral DNA
• Discovered that bacteria have an enzyme that
  chops up viral DNA

5
Specific Cuts

• Restriction enzymes cut DNA at a specific
  nucleotide sequence
• Cuts leave sticky ends on DNA fragments that
  pair with matching cuts

6
Making Recombinant DNA
5
G
A A T T C
3
C T T A A
G
one DNA fragment
another DNA fragment
5
G
A A T T C
3
C T T A A
G
5
3
7
Making Recombinant DNA
nick
5
3
G
A A T T C
3
C T T A A
G
5
nick
DNA ligase action
G
A A T T C
C T T A A
G
8
Using Plasmids

• Plasmid a small circle of bacterial DNA
• Foreign DNA inserted into plasmid
• is replicated and distributed along with plasmid
• Plasmid becomes a cloning vector
• delivers DNA into another cell

9
Cloning Vectors
10
Using Plasmids
e The DNA fragments and plasmid DNA are mixed
with DNA ligase.
a A restriction enzyme cuts a specific base
sequence everywhere it occurs in DNA.
b The DNA fragments have sticky ends.
f The result? A collection of recombinant
plasmids that incorporate foreign DNA fragments.
c The same enzyme cuts the same sequence in
plasmid DNA.
d The plasmid DNA also has sticky ends
g Host cells that can divide rapidly take up the
recombinant plasmids.
Fig. 11-3, p.164
11
Gene Libraries

• Cells that host fragments of cloned DNA
• Genomic library

12
Where am I?

• 123 Devilbiss
• Biology 101
• SU
• US
• Earth

13
DNA Sequencing

• Order of fluorescent bands indicates DNA sequence

14
Polymerase Chain Reaction

• Sequence to be copied is heated
• Primers are added and bind to ends of single
  strands
• DNA polymerase uses free nucleotides to create
  complementary strands
• Doubles number of copies of DNA

15
Polymerase Chain Reaction
double-stranded DNA to copy
16
Polymerase Chain Reaction
mixture heated again makes all DNA fragments
unwind
17
DNA Fingerprints

• Unique array of DNA fragments
• Inherited from parents in Mendelian fashion
• Even full siblings can be distinguished from one
  another by this technique

18
Analyzing DNA Fingerprints

• DNA is separated by gel electrophoresis
• Pattern of bands is used to
• Identify or rule out criminal suspects
• Identify bodies
• Determine paternity

19
A DNA Fingerprint
20
DNA Sequence Data

• Evolutionary trends
• Potential therapies for genetic diseases
• Data bases using computer technology

21
Genetics in Practice

• Genetic engineering is used to change genetic
  makeup of organisms
• Genes transferred between species (Transgenic
  organisms)
• Genes modified and reinserted into same species

22
Transgenic Plants

• Contain DNA from another species
• New genes make crop plants less vulnerable to
  disease and pests
• Use bacterial cloning vectors to insert foreign
  gene (Ti plasmid)

23
Transgenic Cotton

• Resistant to herbicides
• Insecticide gene

24
Genetically Engineered Bacteria

• Produce medically valuable proteins
• Breakdown environmental contaminants
• Designed to survive only under narrow conditions

25
Transgenic Animals

• Early experiments in mice
• Injection of rat gene corrected a growth-hormone
  deficiency
• Injection of human growth-hormone gene produced
  giant mice
• Human genes are now routinely transferred into
  animals to produce human proteins for use as drugs

26
Genetically Modified Animals
27
Gene Therapy For SCID-X1

• Designed to cure bubble babies
• Immune system cant fight infection

28
Gene Therapy For SCID-X1

• Retrovirus inserts normal allele into cultured
  stem cells
• Modified stem cells returned to childs bone
  marrow
• Successfully created immune function
• Also caused leukemia in some children

29
Who Gets Enhanced?

• Eugenic engineering
• Selecting for desirable human traits
• How should we use gene therapy?
• Who should decide what genetic traits can or
  should be altered?

30
Xenotransplantation

• Human organs are in short supply
• Pig organs are similar, but human body rejects
  them as foreign
• Scientists work to knockout pig genes that
  trigger rejection
• Can interspecies transplants introduce new
  diseases to humans?

31
Frankenfood

• Genetically engineered foods are widespread in
  the US
• Cut costs, reduce herbicide use, enhance yields
• What effect will they have on humans and
  ecosystems?

32
Transgenic Mouse

• With genes for fluorescent protein