Transcript Chapter 1

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Powerpoint Lecture Outline
Human Genetics
Concepts and Applications
Eighth Edition
Ricki Lewis
Prepared by
Dubear Kroening
University of
Wisconsin-Fox Valley
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Chapter 19
Genetic Technologies:
Amplifying, Modifying, and
Monitoring DNA
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Biotechnology
• Use or alteration of cells
or biological molecules for
specific application
• Transgenic organisms are
possible, but the genetic
code is universal
• Ethical and legal issues to Figure 19.1
be considered including
patent laws
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Transgenic Animals
• Have genetic modifications and carry
that genetic alteration from other
organisms in all of their cells
• Recombinant DNA – bacteria making
human insulin
• Patenting issues
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Technology Timeline
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Amplifying DNA
• Polymerase chain reaction (PCR)
– Increases the amount of a DNA sequence
in a tube
– Replicates sequence millions of times
• Recombinant DNA technology
– Amplifies DNA within cells often using
sequences from other organisms
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Uses of PCR
Table 19.1
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Figure 19.2
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Transcription-Mediated Amplification
• Copies target DNA into RNA and then
uses RNA polymerase to amplify RNA
• Does not require temperature shifts
• Makes 10 billion copies in ½ hour
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Recombinant DNA
• Recombinant DNA is a molecule that combines
DNA from two sources, also known as gene
cloning
• Creates a new combination of genetic material
• Human gene for insulin was placed in bacteria to
make large quantities for diabetics
• Genetically modified organisms are possible
because of the universal nature of the genetic
code
• Safety concerns
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Creating Recombinant DNA Molecules
• Cut DNA from donor and recipient with the
same restriction enzymes
• Cut DNA fragment is combined with a vector
• Vector DNA moves and copies DNA fragment of
interest
• Vector cut with restriction enzymes
• The complementary ends of the DNAs bind and
ligase enzyme reattaches the sugar-phosphate
backbone of the DNA
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Creating Recombinant DNA
Molecules
Figure 19.3a
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Figure 19.3b
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Figure 19.3c
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Vectors
• Are DNA molecules that can be moved into
and replicated in an organism
• They are classified by
– The organisms that replicated the vector
– The size of DNA that can be inserted
Table 19.2
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Plasmids
Figure 19.4
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Recombinant DNA
Figure 19.5
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Isolating Gene of Interest
• Genomic library
– Collections of recombinant DNA that contain
pieces of the genome
• DNA probe
– Radioactively (or fluorescently) labeled gene
fragments
• cDNA library
– Genomic library of protein encoding genes
produced by extracting mRNA and using reverse
trancriptase to make DNA
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Figure 19.6
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Selecting Recombinant Molecules
• Three types of cells can result from
attempt to introduce a DNA molecule into
a bacterial cell:
– Cells lack plasmid
– Cells contain plasmid that do not
contain foreign genes
– Cells that contain plasmids with
foreign genes
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Selecting for Cells with Vectors
• Vectors are commonly engineered to
carry antibiotic resistance genes
• Host bacteria without a plasmid die in
the presence of the antibiotic
• Bacteria harboring the vector survive
• Growing cells on media with antibiotics
ensures that all growing cells must carry
the vector
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Selecting Cells with Inserted DNA
• The site of insertion of the DNA of interest
can be within a color-producing gene on
the vector
• Insertion of a DNA fragment will disrupt
the vector gene and there will be a lack of
color
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Applications of Recombinant DNA
Recombinant DNA is used to:
• Study the biochemical properties or genetic
pathways of that protein
• Mass produce a particular protein (e.g., insulin)
• Sometimes conventional methods are still the
better choice
• Textile industry can produce indigo dye in E. coli
by genetically modifying genes of the glucose
pathway and introducing genes from another
bacterial species
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Table 19.3
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Transgenic Organisms
• When recombinant DNA is applied to
multicellular organisms, individuals must be
bred to yield homozygous individuals
• Plants may be produced by asexual
reproduction (cuttings)
• Different vectors and gene transfer
techniques can be used
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Making a Transgenic Plant
Figure 19.7
May use Ti plasmids to obtain foreign DNA
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Bt Insecticide gene
• From bacterium Bacillus thuringiensis
(bt)
• Specifies a protein that destroys the
stomach lining of certain insect larva
• 2/3 of U.S. corn is transgenic for the bt
gene
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Table 19.4
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Table 19.5
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Transgenic Animals
• More difficult than plants
• Several techniques to insert DNA
– Chemicals to open holes in plasma membrane
and liposomes carry DNA in cells
– Electroporation–a brief jolt of electricity to open
membrane
– Microinjection – uses microscopic needles
– Particle bombardment – a gun like device
shoots metal particles coated with foreign DNA
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Table 19.6
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Figure 19.8
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Bioremediation
• Transgenic organisms can provide
process as well as products
• Ability to detoxify pollutants
• Examples
– Hg-contaminated soils
– GFP gene reveal locations of land mines
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Monitoring Gene Function
• Gene Expression Profiling
– Indicates genes transcribed
• DNA Variation Screening
– Detects mutations in Single Gene
Polymorphisms (SNPs)
• Microarray Comparative Genomic
Hybridization
– Deletions and amplifications of DNA
sequences between cells or species
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Figure 19.9
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Figure 19.9
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Figure 19.9
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Table 19.7
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Figure 19.10
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Solving a Problem
Figure 19.11
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