Chapter 13 Genetic Engineering

Chapter 13 Genetic Engineering
• Selective Breeding- choosing what parents you
want to produce offspring for the next
generation.
• What do get when you cross a bull dog and a
shitzu?
• Hybridization- Crossing dissimilar individuals to
bring together the best of both organisms.
• Hybrid Vigor- phenomenon, offspring are better
than the parents.

• Inbreeding is the continued breeding of
individuals with similar characteristics.
– Risky, because it could bring out the
recessive alleles and cause a genetic defect.
Blindness, joint problems

Increase Variation
• Why would humans want to increase
variations?
– Better the species
– Make the mutation occur faster
– More variety

Manipulating DNA
• Scientist change DNA by
– Extracting DNA from cells
– Cut into smaller pieces
– Identify the sequence of bases on the DNA
molecule
– Make unlimitied copies of DNA

DNA Extraction
• Cells are opened up and DNA is
separated from other parts of the cell

Cutting DNA
• DNA is cut into small fragments by
restriction enzymes. (Cuts DNA at a
specific nucleotide sequence…very
precise)

Separating DNA
• Gel Electrophoresis- DNA Fragments are
placed in certain gel wells and an electric
voltage is passed through them.
• DNA molecules move toward the opposite
end of the gel.
• Smaller DNA fragments move faster
through the gel.

Using the DNA Sequence
• The DNA Sequence can be read, studied,
or changed.
• Compare genes with other organisms.
• Recombinant DNA- produced by
combining DNA from different sources.

Making Copies
• In order to study genes, it helps to make
copies.
• PCR (Polymerase Chain Reaction)-
makes many copies of DNA through a
process of heating and cooling using DNA
polymerase.

13.4 Applications of Genetic
Engineering
• Transgenic Organisms- organisms contain
genes from other organisms.
– Example: The enzyme (luciferase) from fire
flies was transferred into a tobacco plant cell.
– What do you think happens?
• The plant glows at dark…page 331

Why make transgenic organisms?
• Resist pests, herbicides, harsh conditions
• Improve nutritional value, shelf life
• Test and study
• Medical purposes…insulin, growth
hormone, clotting factors
• Transgenic Animals can produce more
milk, less fat, human proteins

Cloning
• Cloning is producing genetically identical
cells from a single cell.
– Bacteria is easy to clone (unicellular)
– What about multicellular organisms?
– Ian Wilmut cloned the first sheep. DOLLY.

Cloning Process

To Clone or Not to Clone?