key concept genetic engineering is about changing the …...9.4 genetic engineering genetic...
TRANSCRIPT
9.4 Genetic Engineering
KEY CONCEPT
Genetic Engineering is about changing the DNA
sequences of organisms.
9.4 Genetic Engineering
Genetic Engineering Technique #1:
Entire organisms can be cloned.
• A clone is a genetically identical copy of a gene or of
an organism.
CC, short for Copy
Cat, is the first
successfully cloned
Cat.
The original
cat
9.4 Genetic Engineering
• Cloning occurs in nature.
– bacteria (binary fission)
– some plants (from roots)
– some simple animals (budding, regeneration)
9.4 Genetic Engineering
• Mammals can be cloned through a process called nuclear
transfer.
– nucleus is removed from an egg cell
– nucleus of a cell from the animal to be cloned is
implanted in the egg
9.4 Genetic Engineering
One of first mammals to be successfully cloned was a sheep.
9.4 Genetic Engineering
The adult sheep is Dolly,
the first mammal cloned
from an adult cell.
The lamb is Dolly’s
offspring, called Bonnie.
9.4 Genetic Engineering
• Cloning has potential benefits.
– organs for transplant into humans
– save endangered species
• Cloning raises concerns.
– low success rate
– clones “imperfect” and less healthy than original animal
– decreased biodiversity
9.4 Genetic Engineering
Genetic Engineering Technique #2: Recombinant DNA
New genes can be added to an organism’s DNA.
• Genetic engineering involves changing an organism’s
DNA to give it new traits.
• Genetic engineering is based on the use of
recombinant DNA.
• Recombinant DNA contains genes from more than
one organism.
(bacterial DNA)
9.4 Genetic Engineering
• Process involves:
– Bacterial plasmids are often used to make
recombinant DNA.
– Steps:
1. plasmids are loops of
DNA in bacteria
2. restriction enzymes cut
plasmid and foreign DNA
3. foreign gene inserted
into plasmid
9.4 Genetic Engineering
Genetic Engineering Technique #3: GMO’s
A GMO = a “Genetically Modified Organism”
• A “GMO” or transgenic organism has one or more
genes from another organism inserted into its genome.
9.4 Genetic Engineering
• GMO (Transgenic) bacteria can be used to produce
human proteins.
– gene inserted into plasmid
– plasmid inserted into bacteria
– bacteria express the gene
• GMO (Transgenic) plants are common in agriculture.
– transgenic bacteria
infect a plant
– plant expresses
foreign gene
– many crops are now
genetically modified
(GM)
9.4 Genetic Engineering
Examples of how transgenic bacteria and plants are
being used:
1. Transgenic Bacteria
Now make insulin, growth hormone, and clotting
factor cheaply and in great abundance)
2. Transgenic Plants
52% of soybeans and 25% of corn are transgenic
Different varieties are resistant to disease,
produce their own insecticide, resist weed-killing
chemicals, and/or have increased vitamin content
9.4 Genetic Engineering
• GMO (Transgenic) animals are used to study
diseases and gene functions.
– Ex. transgenic mice used to study development
and disease
– gene “knockout mice” used to study gene function
Knockout mouse on left lacks gene for protein leptin,
which helps to control food intake. Used in obesity studies.
9.4 Genetic Engineering
• Can Genetic Engineering be used to bring back extinct
species or save endangered species?
https://www.youtube.com/watch?v=68QhIQLeVUA
9.4 Genetic Engineering
• Cloning: National Geographic Video
• http://www.youtube.com/watch?v=dfqwUlnsGvY
9.4 Genetic Engineering
• Scientists have concerns about some uses of genetic
engineering.
– possible long-term health effects? of eating GM foods
– possible effects of GM plants on ecosystems and
biodiversity ?
9.4 Genetic Engineering
Place in Science Fiction
• Jessica Alba as “Max” in the SciFi TV series
“Dark Angel”