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Chapter 20
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DNA and Biotechnology
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DNA molecule
DNA Is a Double Helix
Consisting of Two Strings of
Nucleotides
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During Replication of DNA
Each Original Strand Serves
As a Template for a New
Strand
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This process is also used by Man to
determine the sequence of DNA
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Semiconservative
replication
Each new strand
has half an original
strand
DNA Sequencing
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Figure 20.1
Gel Electrophoresis
Figure 20.1 (2 of 3)
DNA Sequencing
Figure 20.1 (3 of 3)
DNA Codes for RNA, Which Codes
for a Protein
This is the central dogma of DNA
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transcription
This RNA Molecule will be translated by Ribosomes
into a protein. This protein has an activity that will
give us a phenotype
DNA Codes for RNA, Which
Codes for a Protein
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Translation is protein synthesis
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the genetic code
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Table 17.7 page 405 (from ch 17)
A codon is 3 nucleotides together
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Each codon, represents a specific Amino Acid
Changes in a sequence, will change a codon
which will change the protein
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Codons and their AA
Fig 17.7
The Human Genome Project
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An effort to sequence the entire human
genome
What Does it do
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Function
Change over time
Identify disease/health
Sequencing
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Genetic Map
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Figure 20.12 (1/4)
Now we know the sequence
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What tools do we have and how can we use
them.
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Recombinant DNA Technique
Figure 20.3
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What to do when you don’t want or need a
vector?
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Polymerase
Chain
Reaction
(PCR)
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Figure 20.5 (1/2)
Polymerase
Chain
Reaction
(PCR)
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Figure 20.5 (2/2)
Genetic Engineering Is the
Manipulation of DNA for
Human Purposes
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Recombinant DNA is made of DNA from
different sources
Humans can not mix and match various
genes from different organisms
This allows us to do things in a few years
which previously would take deckades
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Laboratory-Modified DNA
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Recombinant DNA: cutting, splicing, copying
DNA
Restriction enzymes
DNA ligases
Plasmids
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Recombinant
DNA Technique
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Figure 20.4
Genetic Engineering:
Transgenic Organisms
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Transgenic bacterial uses to make bioactive
molecules (medicine):
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Insulin
Human growth hormone
Erythropoeitin
Tissue plasminogen activator (tPA)
Vaccines
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Genetic Engineering:
Transgenic Organisms
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Transgenic plants:
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Increased resistance to freezing
Longer shelf life of fruits and vegetables
Increased vitamin A (and overall nutrition)
Edible vaccines
Human proteins (i.e., albumin) (when required in very
large amounts)
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Transgenic Animals
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Bigger challenges:
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No plasmid use
Cloning more difficult
Successes:
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Bovine growth hormone for faster animal growth
“Gene farming”
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Genetic Engineering Is the
Manipulation of DNA for
Human Purposes
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Recombinant DNA is made of DNA from
different sources
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Genetic Engineering Is the
Manipulation of DNA for
Human Purposes
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Gene therapy replaces faulty genes with functional
genes
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methods of delivering a healthy gene
examples of conditions suitable for gene therapy
Faulty information in mRNA may someday be
correctable
Gene silencing may someday adjust gene activity
DNA fingerprinting can identify individuals
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Gene Therapy: Hope of the
Future
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Obstacles:
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Transplant into “right” cells
Into reproductive cells?
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Vectors
Transfer
Genes to
Human Cells
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Figure 20.13
Vectors Transfer Genes to
Human Cells (cont.)
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Retroviruses
Liposomes
Direct DNA injection
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Gene Therapy Successes
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Severe combined immunodeficiency (SCID)
success
Cystic fibrosis
Cancer research
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Gene therapy
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ornithine transcarboxylase deficiency
(OTCD).
X-linked severe combined immunodeficiency
disease (X-SCID),
Not approved by the FDA
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The Purpose of the Human
Genome Project Is to Identify the
Complete DNA Sequence of the
Human Genome
A way to identify and characterize all the genes and the entire
sequence of the human genome.
Funded by the DOE
A way to look at change in the human genome and health
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over time
What we can do with this
info?
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Individual medicine
Diagnose Disease faster
Identify individuals
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DNA Fingerprint
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Using an individuals unique DNA sequence
and 20 or so specific marker we can
determine who and individual is
Process
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DNA sample cut with restriction enzymes and
separated by size.
Probes that bind to specific sequences of DNA
will highlight their specific matches.
The pattern is used to identify individuals
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