(1) What Is Genetic Engineering?
• Genetic Engineering = Altering the genetic
code of an organism.
• How is this most commonly used?
– Selective Breeding of Plants + Animals
– Selective Breeding
– Gene Therapy
– Cell Transformation
(2) Selective Breeding
• Takes advantage of naturally occurring
genetic variation in plants, animals, and
• Used to control which desired traits pass on
to the next generation.
(3) Gene Therapy
• An absent or faulty gene is replaced with a normal,
• Viruses are often used because they have the ability to
enter a cell’s DNA.
• How Does This Work?
– The virus is modified so that it cannot cause disease.
– A DNA fragment with the replacement gene is spliced to the viral
– The patient is infected with the modified viruses
• Unfortunately, these experiments have not been very
• Gene therapy remains a high-risk, experimental procedure.
(4) Cell Transformation
• Cell Transformation = Genetically Modified
• A cell takes in DNA from outside the cell.
• Can use it to insert desired genes/traits.
• When organisms contains genes from
another species, they are called transgenic
Transgenic Organism Examples
Mice Used to study how the altering of
human-related genes impacts the
Cattle Alter the fat / muscle composition
of the animal.
Plants Can become naturally resistant
to insects and viruses, or contain vitamins.
Bacteria Can produce large quantities,
quickly, of medicines like insulin and
• Clone A member of a population of
genetically identical cells produced from a
• Researchers hope that cloning will enable
them to make copies of transgenic animals
to help save endangered species.