DNA FINGERPRINTING
Instructor
Terry Wiseth
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There are three exercises
to perform for this lab.
Click on the exercise
listed below that you will
be on
performing.
Click
the marker board
on the right side to view
GEL ELECTROPHORESIS
information
and instructions
on the DNA lab
PATERNITY TESTING
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DNA. It's what makes you unique.
It's the stuff that tells each and
every one of your body's 10 trillion
cells what it's supposed to be and
what it's supposed to do. And
although your DNA is different from
that of every other person in the
world -- unless you have an
identical twin -- it's the same in
every cell that makes up your body.
DNA FINGERPRINTING
END
LAB
There are three exercises
to perform for this lab.
Click on the exercise
listed below that you will
be performing.
GEL ELECTROPHORESIS
PATERNITY TESTING
DNA FINGERPRINTING
END LAB
END
LAB
DNA FINGERPRINTING
DNA FINGERPRINTING
DNA. It's what makes you
unique. It's the stuff that
tells each and every one of
your body's 10 trillion cells
what it's supposed to be
and what it's supposed to
do. And although your
DNA is different from that
of every other person in
the world -- unless you
have an identical twin -- it's
the same in every cell that
makes up your body.
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That DNA is unique from
person to person but the
same from cell to cell in one
person can be a handy
thing, especially when it
comes to DNA
fingerprinting. DNA
fingerprints can be used for
anything from determining
a biological mother or
father to identifying the
suspect of a crime. And, as
may someday be used to
clear someone's name.
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SLIDE
But what exactly is a DNA
fingerprint? Well, it
certainly isn't an inky
impression of a DNA
strand. Compared to
unimaginably small DNA, a
fingerprint is HUGE. So
what is it that we're looking
at, and how is one of these
fingerprints made?
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Here's your chance to find
out. You'll find out by
solving a mystery -- a crime
of sorts. Solving the
mystery involves creating a
DNA fingerprint (we'll
supply the lab and all
necessary materials) and
comparing this fingerprint
to those of the suspects.
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Your task, as NORTHLAND
Lab's chief technician, is to
create a DNA fingerprint
from the saliva left on a
lollipop. You must then use
the fingerprint to single out
the culprit of this crime. Are
you ready? Then get to
work! Go to the next slide
to get started. Remember
you will need to
answer the
questions 1-5
when you are
finished.
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SLIDE
Part 1: It Takes a Lickin'...
The Crime On the evening
of November 1, at
approximately 8:15 p.m.,
Jimmy Sweet entered his
bedroom, walked over to
his desk, and sat down at
his computer. While
reaching for the computer's
switch he noticed, out of
the corner of his eye, that
one of the items on a
typically well-organized
shelf was out of place.
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Jimmy shot across the
room for a closer
examination. Sure enough,
the object in question had
indeed been disturbed.
The object had been sealed
in an air-tight package. The
package was now ripped
open. The object was still
inside, but it was no longer
in its original condition. In
Jimmy's eyes, it was now
worthless.
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Jimmy pulled out what had
been his most-valued
possession -- his
holographic NOVA lollipop.
The confectionery treat was
now a sticky mess.
Someone had obviously
indulged him- or herself in
its sugary molecules. The
lollipop's holographic
image had been licked
away.
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The Suspects
The prime suspects in this
case are Jimmy's seven
sisters: Candy, Cookie,
Sugar, Lolly, Honey,
Brandee, and Carmela.
Each one of these sisters is
a notorious candy lover and
is easily capable of
committing this crime of
confection.
The suspects have been
detained. DNA fingerprints
of each are available.
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What You Need to Do
Fortunately for this case, a
lollipop cannot be licked
without leaving behind a bit
of saliva. Your task, as
NORTHLAND Lab's chief
technician, is to create a
DNA fingerprint from the
saliva left on the lollipop.
You must then use the
fingerprint to single out the
culprit of this crime.
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SLIDE
Click on the link titled
"It Takes a Lickin'...“
below to get started.
You will be required to be
connected to the internet to
perform this portion of the
lab.
Part 2
It Takes a Licken’…
Questions 1- 5 for
DNA FINGERPRINTING
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GEL ELECTROPHORESIS
GEL ELECTROPHORESIS
Gel electrophoresis is a
method that separates
molecules on the basis of
size, electric charge, and
other physical properties. A
gel is a colloid in a solid
form.
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The term electrophoresis
describes the migration of
charged particle under the
influence of an electric
field. Electro refers to the
energy of electricity.
Phoresis, from the Greek
verb phoros, means "to
carry across."
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Gel electrophoresis refers
to the technique in which
molecules are forced
across a span of gel,
motivated by an electrical
current. Electrodes at either
end of the gel provide the
driving force. A molecule's
properties determine how
rapidly an electric field can
move the molecule
through a
gelatinous medium.
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An individual's DNA is as
distinctive as a fingerprint.
This technique was used to
assist in determining O.J.
Simpson's life. DNA
samples can be obtained
from the trace amounts of
blood or semen. These DNA
samples can be
separated
using gel
electrophoresis.
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The number and position of
bands formed on each lane of
gel is the actual genetic
"fingerprint" of that DNA
sample. The characteristics of
certain segments of DNA vary
from person to person and form
a highly individual, detectable
"genetic fingerprint." Developed
only in the mid-1980s, genetic
fingerprinting has rapidly
become a widely used
courtroom tool.
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In 1988 the first person in the
United States was executed
based on DNA technology.
The likelihood that two
individuals--other than identical
twins--will have the same
genetic fingerprint varies from
about one in 800,000 to about
one in 1 billion. By comparison,
the probability that two
individuals will have the same
conventional
fingerprint is
also about
one in 1 billion.
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SLIDE
But the genetic fingerprint
has many other advantages
over conventional
fingerprints.
It is unusual for police to
find a high-quality
fingerprint at a crime scene,
but much more likely that
they will find blood or
semen. Furthermore, only a
microscopically small
sample is required for a
positive
identification.
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No relationship exists
between the conventional
fingerprints of parents and
children, but the genetic
fingerprints are closely
related because the child
receives half of her or his
genetic information from
each parent. Thus, half the
bands in the child's genetic
fingerprint come from the
mother, and half
from the father.
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This similarity can be used
to establish paternity (or
maternity) with a much
higher degree of certainty
than is possible with other
techniques, such as a blood
test.
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Another application for this
technique involves the
effort to determine whether
bones unearthed seven
years ago in Argentina are
those of Joseph Mengele,
the chief physician at the
Auschwitz concentration
camp who supervised the
systematic extermination of
about 4 million
Jewish men, women,
and children during
World War II.
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On behalf of the German
government, Jeffreys
extracted a small amount of
DNA from one of the bones
and compared it to DNA
from Mengele's son, Rolf
Jenckel, and Jenckel's
mother. In April 1992, he
reported that the bones
were indeed
Mengele's, finally
closing the search
for the sadistic
physician.
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Click on the link below to go to
the interactive lab on Gel
Electrophoresis.
You will be required to be
connected to the internet to
perform this portion of the lab.
When you are finished with the
lab be sure you answer Gel
Electrophoresis questions 1- 4.
PERFORM THE
GEL ELECTROPHORESIS
Questions 1- 4
GEL ELECTROPHORESIS
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PATERNITY TESTING
PATERNITY TESTING
The DNA present in hair
root bulbs, spermatozoa or
any nucleated tissue can be
profiled. It is noteworthy
that red blood cells lose
their nuclei early in their life
span but white blood cells
remain nucleated.
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A few hair roots on a blunt
instrument found in the
possession of a crime
suspect can be matched
against an autopsy blood
sample. Similarly seminal
fluid in the vagina of a rape
victim can be compared
with DNA in the hair or
white blood cells of a
suspect.
Hair root
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Since every cell within an
individual contains the
same DNA there is no need
to match DNA from semen
with semen or from blood
with blood. Samples
commonly examined for
DNA in forensic cases
include liquid blood, blood
stains, semen, saliva,
cellular tissue, hair
root bulbs and
mouth swabs.
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In practice disputed
parentage means disputed
paternity since maternity is
rarely in doubt. Disputes
may arise under the
following circumstances:
1) A married man may allege that his
wife has committed adultery, and that
he is not the father of one or more of
her children.
2) A women who has illegitimate
offspring may allege that a certain man
is the father of that child in order to
obtain an affiliation order against him
and to ensure financial assistance with
the child's upbringing.
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Submission to blood
testing is usually agreed
between the parties and
court orders are seldom
required. Consent is
required, the age of consent
being 16 but the court may
draw inferences from the
fact that a person has failed
to comply with
blood testing.
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Use of DNA profiling for
such purposes is
increasing since it more
positively discriminating
than exclusion by serology.
The practicalities of blood
testing involve adequate
identification of the parties
involved by their legal
representatives
and by means
of photographs.
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SLIDE
Click on the link below to go to
the interactive lab on Paternity
Testing.
You will be required to be
connected to the internet to
perform this portion of the lab.
When you are finished with the
lab be sure you answer Paternity
Testing questions 1-2.
PERFORM THE
PATERNITY TESTING
Questions 1-2 for
PATERNITY TESTING
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• It Takes a Lickin'...