Chapter 13 Genetic Engineering

Chapter 13 Genetic Engineering

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Selective Breeding
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choosing what parents you
want to produce offspring for the next
generation.

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What do get when you cross a bull dog and a
shitzu?

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Hybridization
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Crossing dissimilar individuals to
bring together the best of both organisms.

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Hybrid Vigor
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phenomenon, offspring are better
than the parents.

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Inbreeding is the continued breeding of
individuals with similar characteristics.

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Risky, because it could bring out the
recessive alleles and cause a genetic defect.

Blindness, joint problems

Increase Variation

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Why would humans want to increase
variations?

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Better the species

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Make the mutation occur faster

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More variety

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http://www.techapps.net/interactives/pepp
erMoths.swf


Manipulating DNA

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Scientist change DNA by

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Extracting DNA from cells

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Cut into smaller pieces

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Identify the sequence of bases on the DNA
molecule

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Make unlimitied copies of DNA

DNA Extraction

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

Cutting DNA

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

Separating DNA

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Gel Electrophoresis
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DNA Fragments are
placed in certain gel wells and an electric
voltage is passed through them.

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DNA molecules move toward the opposite
end of the gel.

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Smaller DNA fragments move faster
through the gel.

Using the DNA Sequence

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The DNA Sequence can be read, studied,
or changed.

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Compare genes with other organisms.

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Recombinant DNA
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produced by
combining DNA from different sources.

Making Copies

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In order to study genes, it helps to make
copies.

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PCR (Polymerase Chain Reaction)
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makes many copies of DNA through a
process of heating and cooling using DNA
polymerase.

13.4 Applications of Genetic
Engineering

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Transgenic Organisms
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organisms contain
genes from other organisms.

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Example: The enzyme (luciferase) from fire
flies was transferred into a tobacco plant cell.

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What do you think happens?

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The plant glows at dark…page 331



Why make transgenic organisms?

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Resist pests, herbicides, harsh conditions

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Improve nutritional value, shelf life

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Test and study

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Medical purposes…insulin, growth
hormone, clotting factors

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Transgenic Animals can produce more
milk, less fat, human proteins

Cloning

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Cloning is producing genetically identical
cells from a single cell.

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Bacteria is easy to clone (unicellular)

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What about multicellular organisms?

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Ian Wilmut cloned the first sheep. DOLLY.


Cloning Process

To Clone or Not to Clone?