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Genetic Engineering
Biotechnology
Regents Biology
2006-2007
We have been manipulating DNA
for generations!
 Artificial breeding

creating new breeds of animals & new
crop plants to improve our food
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Animal breeding
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Breeding food plants
 “Descendants” of the wild mustard

the “Cabbage family”
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Breeding food plants
Evolution of modern corn (right) from
ancestral teosinte (left).
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A Brave New World
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The code is universal
 Since all living
organisms…



use the same DNA
use the same code
book
read their genes
the same way
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TACGCACATTTACGTACGCGGATGCCGCGACTATGATC
ACATAGACATGCTGTCAGCTCTAGTAGACTAGCTGACT
human genome
CGACTAGCATGATCGATCAGCTACATGCTAGCACACYC
GTACATCGATCCTGACATCGACCTGCTCGTACATGCTA
3.2
billion
bases
CTAGCTACTGACTCATGATCCAGATCACTGAAACCCTA
GATCGGGTACCTATTACAGTACGATCATCCGATCAGAT
CATGCTAGTACATCGATCGATACTGCTACTGATCTAGC
TCAATCAAACTCTTTTTGCATCATGATACTAGACTAGC
TGACTGATCATGACTCTGATCCCGTAGATCGGGTACCT
ATTACAGTACGATCATCCGATCAGATCATGCTAGTACA
TCGATCGATACTGCTACTGATCTAGCTCAATCAAACTC
TTTTTGCATCATGATACTAGACTAGCTGACTGATCATG
ACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGA
TCATCCGATCAGATCATGCTAGTACATCGATCGATACT
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Can we mix genes from one creature
to another?
YES!
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Mixing genes for medicine…
 Allowing organisms to produce new
proteins
bacteria producing human insulin
 bacteria producing human growth hormone

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How do we do mix genes?
 Genetic engineering
find gene
 cut DNA in both organisms
 paste gene from one creature into other
creature’s DNA
 insert new chromosome into organism
 organism copies new gene as if it were its
own
 organism reads gene as if it were its own
 organism produces NEW protein:
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Remember: we all use the same genetic code!

Cutting DNA
 DNA “scissors”

enzymes that cut DNA

restriction enzymes
 used by bacteria to cut up DNA of
attacking viruses
 EcoRI, HindIII, BamHI

cut DNA at specific sites
 enzymes look for specific base sequences
GTAACG|AATTCACGCTT
GTAACGAATTCACGCTT
CATTGCTTAA|GTGCGAA
CATTGCTTAAGTGCGAA
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Restriction enzymes
 Cut DNA at specific sites

leave “sticky ends”
restriction enzyme cut site
GTAACGAATTCACGCTT
CATTGCTTAAGTGCGAA
restriction enzyme cut site
GTAACG AATTCACGCTT
CATTGCTTAA GTGCGAA
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Sticky ends
 Cut other DNA with same enzymes


leave “sticky ends” on both
can glue DNA together at “sticky ends”
GTAACG AATTCACGCTT
CATTGCTTAA GTGCGAA
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gene
you want
GGACCTG AATTCCGGATA
CCTGGACTTAA GGCCTAT
chromosome
want to add
gene to
GGACCTG AATTCACGCTT
CCTGGACTTAA GTGCGAA
combined
DNA
Sticky ends help glue genes together
cut sites
gene you want
cut sites
TTGTAACGAATTCTACGAATGGTTACATCGCCGAATTCACGCTT
AACATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGTGCGAA
AATTCTACGAATGGTTACATCGCCG
GATGCTTACCAATGTAGCGGCTTAA
sticky ends
cut sites
isolated gene
chromosome want to add gene to
AATGGTTACTTGTAACG AATTCTACGATCGCCGATTCAACGCTT
TTACCAATGAACATTGCTTAA GATGCTAGCGGCTAAGTTGCGAA
DNA ligase joins the strands
sticky ends stick together
Recombinant DNA molecule
chromosome with new gene added
TAACGAATTCTACGAATGGTTACATCGCCGAATTCTACGATC
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CATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGATGCTAGC
How can
bacteria read
human DNA?
Why mix genes together?
 Gene produces protein in different
organism or different individual
human insulin gene in bacteria
TAACGAATTCTACGAATGGTTACATCGCCGAATTCTACGATC
CATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGATGCTAGC
“new” protein from organism
ex: human insulin from bacteria
aa aa aa aa aa aa aa aa aa aa
bacteria
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human insulin
Uses of genetic engineering
 Genetically modified organisms (GMO)

enabling plants to produce new proteins
 Protect crops from insects: BT corn
 corn produces a bacterial toxin that kills corn
borer (caterpillar pest of corn)
 Extend growing season: fishberries
 strawberries with an anti-freezing gene from
flounder
 Improve quality of food: golden rice
 rice producing vitamin A
improves nutritional value
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Bacteria
 Bacteria are great!
one-celled organisms
 reproduce by mitosis

 easy to grow, fast to grow
 generation every ~20 minutes
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Bacterial DNA
 Single circular chromosome
only one copy = haploid
 no nucleus

 Other DNA = plasmids!
bacteria
chromosome
plasmids
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There’s more…
 Plasmids
small extra circles of DNA
 carry extra genes that bacteria can use
 can be swapped between bacteria

 bacterial sex!!
 rapid evolution = antibiotic resistance

can be picked up
from environment
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How can plasmids help us?
 A way to get genes into bacteria easily
insert new gene into plasmid
 insert plasmid into bacteria = vector
 bacteria now expresses new gene

 bacteria make new protein
gene from
other organism
cut DNA
plasmid
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recombinant
plasmid
+
vector
glue DNA
transformed
bacteria
Grow bacteria…make more
gene from
other organism
recombinant
plasmid
+
vector
plasmid
grow
bacteria
harvest (purify)
protein
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transformed
bacteria
Applications of biotechnology
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I’m a very special pig!
Got any Questions?
Regents Biology
2006-2007
Biotechnology
Gel Electrophoresis
Regents Biology
2006-2007
Many uses of restriction enzymes…
 Now that we can cut DNA with
restriction enzymes…
we can cut up DNA from different
people… or different organisms…
and compare it
 why?

 forensics
 medical diagnostics
 paternity
 evolutionary relationships
 and more…
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Comparing cut up DNA
 How do we compare DNA fragments?

separate fragments by size
 How do we separate DNA fragments?
run it through a gelatin
 gel electrophoresis

 How does a gel work?
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Gel electrophoresis
 A method of separating
DNA in a gelatin-like
material using an electrical
field
DNA is negatively charged
 when it’s in an electrical
field it moves toward the
positive side

DNA 
–
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
“swimming through Jello”
+
Gel electrophoresis
 DNA moves in an electrical field…

so how does that help you compare DNA
fragments?
 size of DNA fragment affects how far it travels
 small pieces travel farther
 large pieces travel slower & lag behind
DNA 
–
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
“swimming through Jello”
+
Gel Electrophoresis
DNA &
restriction enzyme
longer fragments
wells
power
source
gel
shorter fragments
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+
completed gel
fragments of DNA
separate out based
on size
Running a gel
cut DNA with restriction enzymes
1
2
Stain DNA


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ethidium bromide
binds to DNA
fluoresces under
UV light
3
DNA fingerprint
 Why is each person’s DNA pattern different?

sections of “junk” DNA
 doesn’t code for proteins
 made up of repeated patterns
 CAT, GCC, and others
 each person may have different number of repeats
 many sites on our 23 chromosomes with
different repeat patterns
GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT
CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
GCTTGTAACGGCATCATCATCATCATCATCCGGCCTACGCTT
Regents CGAACATTGCCGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA
Biology
DNA patterns for DNA fingerprints
Allele 1
cut sites
repeats
cut sites
GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT
CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
Cut the DNA
GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTT
CGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA
1
2
– DNA 
allele 1
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3
+
Differences between people
Person 1
cut sites
cut sites
GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT
CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
Person 2: more repeats
GCTTGTAACGGCCTCATCATCATCATCATCATCCGGCCTACGCTT
CGAACATTGCCGGAGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA
1
2
DNA fingerprint
– DNA 
person 1
person 2
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3
+
Uses: Evolutionary relationships
 Comparing DNA samples from different
organisms to measure evolutionary
relationships
turtle snake rat squirrel fruitfly
–
DNA

+
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1
2
3
4
5
1
2
3
4
5
Uses: Medical diagnostic
 Comparing normal allele to disease allele
chromosome
with normal
allele 1
chromosome with
disease-causing
allele 2
–
DNA

Example: test for Huntington’s disease
+
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Uses: Forensics
 Comparing DNA sample from crime
scene with suspects & victim
suspects
S1 S2 S3
crime
scene
V sample
–
DNA

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+
DNA fingerprints
 Comparing blood
samples on
defendant’s clothing
to determine if it
belongs to victim

DNA fingerprinting
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RFLP / electrophoresis use in forensics
 1st case successfully using DNA evidence

1987 rape case convicting Tommie Lee Andrews
“standard”
semen sample from rapist
blood sample from suspect
“standard”
How can you
compare DNA from
blood & from semen?
RBC?
“standard”
semen sample from rapist
blood sample from suspect
“standard”
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Electrophoresis use in forensics
 Evidence from murder trial

Do you think suspect is guilty?
blood sample 1 from crime scene
blood sample 2 from crime scene
blood sample 3 from crime scene
“standard”
blood sample from suspect
OJ Simpson
blood sample from victim 1
N Brown
blood sample from victim 2
R Goldman
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“standard”
Uses: Paternity
 Who’s the father?
Mom
F1
–
DNA

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+
F2
child
I’m a-glow!
Got any Questions?
Regents Biology
2006-2007
Using Stem Cells
 A stem cell is a cell that can continuously
divide and differentiate into various tissues.
 Some stem cells have more potential to
differentiate than others.
 Adults’ bodies have some multipotent cells
that can be removed, frozen or cultured, and
used for medical treatments.
 The cells of new embryos have more potential
uses.
 The use of embryos for stem cell research
poses ethical problems.
 An alternative source of embryonic stem cells
is through SCNT (somatic cell nuclear
Regentstransplant).
Biology
What are Stem Cells?
Stem Cells are extraordinary
because:
• They can divide and make
identical copies of themselves over
and over again (Self-Renewal)
• Remain Unspecialized with no
‘specific’ function or become . . . .
• Specialized (Differentiated) w/ the
potential to produce over 200
different types of cells in the body.
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The Major Types of Stem Cells
A. Embryonic Stem Cells
• From blastocysts left over from In-Vitro
Fertilization in the laboratory
• From aborted fetuses
B. Adult Stem Cells
• Stem cells have been found in the blood,
bone marrow, liver, kidney, cornea,
dental pulp, umbilical cord, brain, skin,
muscle, salivary gland . . . .
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http://commons.wikimedia.org/wiki/Image:Stem_cells_diagram.png
Advantages and Disadvantages to
Embryonic and Adult Stem Cells.
Embryonic S.C.
Adult S.C.
“Pluripotent”
(can become any cell)
“Multipotent”
(“can become many but
not any”)
Less Stable. Capacity for
self-renewal is limited.
Difficult to isolate in adult
tissue.
Stable. Can undergo
many cell divisions.
Easy to obtain but
blastocyst is destroyed.
Possibility of rejection?? Host rejection minimized
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Biology
http://www.pbs.org/newshour/bb/science/jan-june14/stemcells_01-29.html
Reprinted with permission of Do No Harm. Click on image for link to website.
 http://www.youtube.com/watch?v=7Ql
WBnL0zjU
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Why is Stem Cell Research So Important to All
of Us?
Stem cells allow us to study how
organisms grow and develop over
time.
Stem cells can replace diseased or
damaged cells that can not heal or
renew themselves.
We can test different substances
(drugs and chemicals) on stem
cells.
We can get a better understanding
of our “genetic machinery.”
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What Human Diseases are Currently
Being Treated with Stem Cells?
 Parkinson’s Disease
 Leukemia (Bone Marrow Transplants)
 Skin Grafts resulting from severe
burns
Stem Cell Therapy has the Potential to:
 Regenerate tissues/organs
 Cure diseases like diabetes, multiple
sclerosis, etc.
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Why the Controversy Over Stem cells?
 Embryonic Stem cells are derived
from extra blastocysts that would
otherwise be discarded following
IVF.
 Extracting stem cells destroys the
developing blastocyst (embryo).
-Questions for ConsiderationIs an embryo a person?
Is it morally acceptable to use
embryos for research?
When do we become “human
beings?”
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Key Concept Questions
 How are transgenic organisms useful to
human beings?
 Genetic engineering has spurred the
growth of biotechnology, a new industry
that is changing the way we interact with
the living world
 How are cloning and stem cell research
related?
 Cloning can produce organisms that are
genetically identical to preexisting
individuals. Stem cells can be used to
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Biologynew tissues.
grow