Transcript Genetic Engineering

Frontiers of Biotechnology
Changing the Living World
• These dogs are all of
the same species
• Where do their
striking differences in
appearance come
from?
Beef Cattle Breeds
Selective Breeding
• A method of improving a species by
allowing only those individual organisms
with desired characteristics to produce the
next generation
– Nearly all domestic animals and crop plants
have been produced by selective breeding
Luther Burbank
• American botanist
1849 – 1926
• Developed more than
800 varieties of plants
in his lifetime
– Developed disease
resistant potato to help
fight Irish potato blight
Hybridization
• Breeding technique
that involves crossing
dissimilar individuals
to bring together the
best traits of both
organisms
Inbreeding
• The continued
breeding of
individuals with
similar characteristics
– Breeds developed
through inbreeding are
genetically similar
– Increased chances of
bringing together two
recessive alleles for
genetic defects
Increasing Variation
• Breeders can increase genetic variation in a
population by
– Inducing mutations
• Mutations are the ultimate source of
genetic variability
Variation – New Kinds of
Bacteria
• Mutation rates increased by using radiation
or chemicals
– Increases the chances of producing a useful
mutant
• Hundreds of useful bacterial strains have
been produced
Variation – New Kinds of Plants
• Polyploid plants
– Plants with double or triple the normal number
of chromosomes
– Produced by using drugs that prevent
chromosomes from separating during meiosis
Manipulating DNA
Tools of Molecular Biology
• DNA extraction
– DNA can be extracted from cells by simple chemical
procedures
• Cutting DNA
– DNA can be cut into smaller fragments by the use of
restriction enzymes
• Separating DNA
– Gel electrophoresis – procedure used to produce DNA
“fingerprints”
Cell Transformation
• During transformation, a cell takes in DNA
from outside the cell
– External DNA becomes a part of the cell’s DNA
Transforming Bacteria
Transforming Plant Cells
Transforming Animal Cells
• Can be transformed in
some of the same
ways as plant cells
• Has applications in
gene replacement
therapy
Applications of Genetic
Engineering
• Transgenic organisms
– Transgenic organisms contain genes from other
organisms
• Transgenic microorganisms
• Transgenic animals
• Transgenic plants
Cloning
• Clone
• A member of a population of genetically identical
cells produced from a single cell
Cloning Dolly
A donor cell is taken from a sheep’s udder.
The nucleus of this cell will provide the genetic
material for the cloned lamb.
An egg cell is taken from a second sheep.
The nucleus of the cell is removed.
This cell does not supply any genetic material for
the cloned lamb.
The donor cell (with a nucleus) and the egg cell
(without a nucleus) are fused using an electric shock.
The fused cells begin dividing normally, forming
an embryo.
The embryo is placed in the uterus of a foster
mother.
The embryo develops into a lamb, Dolly.
Dolly is a clone of the sheep that donated the udder
cell.
A cross between dissimilar individuals to bring
together their best characteristics is called
a. genetic engineering
b. inbreeding
c. hybridization
d. sequencing
Crossing individuals with similar characteristics so
that those characteristics will appear in the offspring
is called
a. inbreeding
b. electrophoresis
c. hybridization
d. genetic engineering
Varieties of purebred dogs are maintained by
a. selective breeding
b. hybridization
c. inbreeding
d. genetic engineering
Changing the DNA of an organism is called
a. genetic engineering
b. hybridization
c. selective breeding
d. inbreeding