Download Copying DNA: Southern Blotting

CHAPTER 15:
MAIN TOPICS
Selective Breeding
Southern Blotting
Polymerase Chain Reaction
Recombinant DNA
Transgenic organisms
Cloning
GMO’s
SELECTIVE BREEDING
Selective breeding:
Breeding organisms for
particular traits
Results in new genetic strains
(varieties)
 150 dog breeds
Types of selective breeding:
Inbreeding
Hybridization
Induced mutations
SELECTIVE BREEDING
Inbreeding
Mating 2 closely related
organisms
Decreases
heterozygosity
Genetic disorders on
recessive alleles
Commonly used by dog
breeders
SELECTIVE BREEDING
Hybridization
Combining different
varieties of organisms
Farm animals/crops
grow faster and bigger
BEEFALO
(combination of cattle and a buffalo)
BIOTECHNOLOGY
Biotechnology: Any
application that uses living
organisms to produce
offspring that have a
specific purpose.
Induced Mutations
Increases genetic variation
Examples: Bacterial mutations
and polyploid plants
BIOTECHNOLOGY
Bacterial Mutations
Increased by radiation
or chemicals
Mostly bad mutations
but occasional good
mutations
Creates beneficial
bacterial strains
BIOTECHNOLOGY
Polyploid plants result from introducing a
drug that induces nondisjunction.
Many chromosomes per cell.
Plants are larger/stronger than diploids.
SOUTHERN BLOTTING: USED TO FIND A
PARTICULAR GENE OF INTEREST.
Steps of Southern Blotting
Restriction enzymes split DNA
Gel electrophoresis separates fragments
COPYING DNA
POLYMERASE CHAIN REACTION
P C R I S A R A P I D M E T H O D F O R C LO N I N G G E N E S
1 DNA is heated into separate strands
2 The mixture is cooled, and primers bind to strands
3 DNA polymerase adds nucleotides to strands, producing two
complementary strands.
4 The procedure is repeated starting at step 1 .
CHANGING DNA
Recombinant DNA
technology allows for a
change in the genetic
composition of living
organisms
Involves producing a
custom built DNA and
incorporating it into living
cells
CHANGING DNA
Steps In Combining DNA Fragments
Step 1: Restriction enzymes cut DNA making
sticky ends
Step 2: These sequences are combined with the
DNA of the organism you want to change
(recombinant DNA)
CHANGING DNA
Plasmids
Circular bacterial
DNA molecules
Scientists combine a
DNA fragment to
plasmids to make
recombinant DNA.
CHANGING DNA
The production of human growth hormone
using Plasmid DNA Transformation
CHANGING DNA
Plasmids and Genetic
Markers
Genetic markers are
genes that make it
possible to distinguish
bacteria that have been
transformed by a
plasmid from those that
have not.
TRANSGENIC ORGANISMS
Transgenic organisms are produced by the
insertion of recombinant DNA into the
genome of a host organism.
TRANSGENIC PLANTS
CLONING
Ian Wilmut, Scotland, 1997
Cloned A Sheep – Dolly
CLONING DOLLY THE SHEEP
AGRICULTURE AND INDUSTRY
GMOs (Genetically Modified Organisms):
Organisms that have had specific changes
introduced into their DNA
Benefits:
Less expensive food
More nutritious
Less harmful
GM (TRANSGENIC) CROPS
GM crops make up a large % of
soybeans, cotton, and corn
Incorporates recombinant DNA
Bt toxin gene kills insects
making pesticides
unnecessary
APPLICATIONS OF GM ANIMALS
 Cows with added hormones
produce more milk
 Pigs modified produce
leaner meat
 Animals with extra genes for
growth hormone so they
grow faster
 Cows
 Fish (salmon)
 Chickens resistant to
Salmonella
GM ANIMALS
In 2008, U.S
government
approved sale
of meat and
milk from
cloned
animals.
Benefits of cloning:
 Make copies of transgenic
animals (faster than breeding)
 Increase food supply
 Save endangered species
HEALTH AND MEDICINE:
PREVENTING DISEASE
Recombinant DNA has also
been used for medicine
Plants w/ added vitamins
Golden Rice
Animals and plants that
produce antibodies and
antibiotics
Antibacterial goat milk
HEALTH AND MEDICINE:
MEDICAL RESEARCH
Transgenic animals
are often used for
testing treatments of
various diseases
Cancer studies
Alzheimer’s disease
and arthritis
HEALTH AND MEDICINE:
TREATING DISEASE
GMOs can be used to make
proteins to treat diseases
Transgenic microorganisms
can be used to produce
human:
Insulin
Growth Hormone
Clotting Factors
Interferon
HEALTH AND MEDICINE:
TREATING DISEASE
Gene Therapy: The use of recombinant DNA to
treat disorders
Involves using DNA that encodes a functional gene
in order to replace a mutated gene.
PERSONAL IDENTIFICATION:
DNA FINGERPRINTING
Identifies individuals by their DNA
profiles
Paternity tests
Crime Scene Investigations
DNA FINGERPRINTING
CHAPTER 15.4 ESSENTIAL QUESTIONS
What privacy issues
does biotechnology
raise?
Are GM foods safe?
Should genetic
modifications to humans
and other organisms be
closely regulated?
PROFITS AND PRIVACY
Patents
Protect the
integrity of scientific
discoveries
Include DNA sequences, genes, techniques
PRO: Motivates scientists to make new
discoveries
CON: High fees for other companies
PROFITS AND PRIVACY:
GENETIC OWNERSHIP
Tomb of the Unknown
Soldier (Arlington, VA)
Now US military
requires a DNA sample
before serving
PRO: Biotechnology
ensures a future of no
more unknown soldiers
PROFITS AND PRIVACY:
GENETIC OWNERSHIP
CON: DNA samples
for paternity suits or
health insurance
claims
RESULT: Genetic
Information
Nondiscrimination
Act in 2008
SAFET Y OF TRANSGENICS
 PROs of GMOs
 CONs of GMOs
Produce high yields No long-term
for mass production studies of the
Reduce land needed hazards these foods
might present
for agriculture
Insect resistance
Lower cost
may threaten
Insect resistant
beneficial insects
plants prevent
pesticide use
Small farmers may
(healthier and better go out of business
for environment)
ETHICS OF BIOTECHNOLOGY
PRO: Curing diseases
CON: When is
biotechnology going
too far?
Manipulate people’s
physical appearance?
Cloning humans?