Transcript Ch 13 Genetic Engineering

Ch 13 Genetic Engineering
Vocab: selective breeding,
hybridization, inbreeding, genetic
engineering, restriction enzyme,
gel electrophoresis, recombinant
DNA, polymerase chain reaction
(PCR), plasmid, genetic marker,
transgenic, clone
13-1 Changing the Living World
Humans use selective breeding, which takes
advantage of naturally occurring genetic
variation in plants, animals, and other
organisms, to pass desired traits to the
next generation of organisms.
• Ex: dog breeding, horse breeding –
choose parents for their traits, attempts to
make disease resistant plants that have a
high production rate
• Hybridization = crossing dissimilar
organisms
• Inbreeding = continued breeding of
individuals with similar characteristics…
has resulted in the combination of
recessive alleles with genetic defects:
weepy eyes in dogs
Inbreeding
Persian Cat
flat face= breathing
problems
Shar-pei
Huge rolls of skin=
Skin disease
Basset hound
Droopy, baggy eyes=
Prone to eye infection
• Breeders can increase the genetic
variation in a population by inducing
mutation which are the ultimate source of
genetic variability… use radiation and
chemicals.
– New bacteria – oil-digesting to clean up
oil spills
– Polyploidy plants – larger and stronger
plants
13-2 Manipulating DNA
• Scientists use their knowledge of the
structure of DNA and its chemical
properties to study and change DNA
molecules. Different techniques are used
to extract DNA from cells, to cut DNA into
smaller pieces, to identify the sequence of
bases in a DNA molecule, and to make
unlimited copies of DNA.
Genetic engineering = making changes in
the DNA code of a living organism
• Extract DNA from cells
• Cutting DNA with restriction enzymes
• Separate DNA using gel electrophoresis
• Identify the sequence using different dyes
that attach to nitrogen bases
• Make copies using polymerase chain
reaction
Restriction Digest and Gel
Electrophoresis
DNA sequencing
13-3 Cell Transformation
During transformation, a cell takes in DNA
from outside the cell. This external DNA
becomes a component of the cell’s DNA.
Transformation
• Scientists can synthesize a DNA strand
and connect it to a circular DNA molecule
known as a plasmid… which can be found
naturally in bacteria. This bacteria can
then be injected into a plant, and will insert
its DNA into the plant.
• If transformation is successful, the
recombinant DNA is integrated into one of
the chromosomes of the cell.
13-4 Applications of Genetic
Engineering
Genetic engineering has spurred the growth
of biotechnology, which is a new industry
that is changing the way we interact with
the living world.
• Humans construct organisms that are
transgenic and have genes from other
species.
• Transgenic bacteria are being used to
produce insulin, growth hormone, and
clotting factor.
• Transgenic animals: mice, livestock
• Transgenic plants: 52% of soybeans and
25% corn is transgenic or genetically
modified.
Clone = a member of a population of
genetically identical cells produced from a
single cell.
Cloning animals
• Bacteria naturally clone as do plants,
multicellular organisms are more difficult;
1997 Dolly the sheep was cloned
• The possibilities raise many ethical and
moral issues.