DNA Profiling - Teacher

Mimi Faulhaber,

Alex Braun,

Nicholas Pelisek


The analysis of genetic markers can produce a DNA profile.


The field of forensics has been changed by DNA technology.
Forensics is the scientific analysis of evidence for crime

scene
investigations and other legal proceedings. The

most
important application of biology to forensics is DNA profiling.


Everyone has their own DNA profile or sometimes call
fingerprint. A technique to obtain DNA profiles is Gel
electrophoresis. Another way would be to use STRs or short
tandem repeats to compare pieces of DNA.


DNA profiling is used to find out whose blood is left behind
at a crime scene and hopefully catch the criminal. In addition
it can be to find out if a child is really yours. In case someone
claims that you are the father of their child, with DNA
profiling you can find out whether they are truly your child.


Developed by
Kary

Mullis in
1985

◦
Development earned him
Nobel Prize in Chemistry
(1993)


Main function is to copy DNA
that comes from very small
samples

◦
PCR allows DNA to replicate
exponentially


PCR uses primers (small strands
of DNA that join to DNA strands
at start of target sequence)

◦
PCR copies a target sequence,
primers attach to end of
target sequence

◦
2 separate primers are needed
for each PCR (DNA has two
strands)



PCR is a 3
-
step process


Denaturation
: heating causes the
two strands of DNA to separate

◦
Heating can be regulated by a
thermal cycler


Hybridization: primers attach to
DNA strands as the solution
cools


DNA Synthesis: DNA polymerase
is added to solution to complete
replication of DNA


Uses of PCR: copy DNA from
crime scenes, examine fossils
without destroying them, find
genetic disorders in developing
babies


•
Gel Electrophoresis is used
for DNA identifying,
analyzing and purifying. It
can be used to show
similarity between species.

•
Gel electrophoresis is used
for creating a person’s
“DNA fingerprint”

•
Two different types of gel
are used,
agarose

and
polyacrylamide

•
Agarose

is mostly used for
DNA, while
polyacrylamide

is often used for proteins

•
Electrophoresis is done by
dragging DNA molecules
through a gel using a
magnet, as DNA is
negatively charged

•
Larger DNA molecules are
held back by the fibers in
the gel

•
The data forms bands,
which then can be analyzed


1. DNA profiling has greatly
advanced the field of ____.

2. Small fragments of DNA
called ____ are used in a
PCR (Polymerase Chain
Reaction).

3. In the step known as ____,
complementary DNA
strands are separated by
using heat.

4. In gel electrophoresis, DNA
molecules are pulled
through the gel due to their
____ charges.

5. The uses of DNA profiling
include ____, ____, and ____.

1. Forensics

2. Primers

3.
Denaturation

4. Negative

5. Any 3 of following:

•
Identifying criminals from
crime scenes

•
Determining relatives

•
Examining DNA of fossils

•
Discovering genetic
disorders in developing
babies

•
Creating a “DNA fingerprint”

“DNA Profiling.”
Biotechnology Online Home
. Web. 25
Jan. 2012.

“Gel Electrophoresis.”
Colorado.edu
. Web. 25 Jan. 2012

“Gel Electrophoresis of DNA and RNA.”
Arbl.cvmbs.colostate.edu.

15 Jan. 2000. Web. 25 Jan.
2012.

Kreuzer
, Helen and Adrianne Massey.
Recombinant
DNA and Biotechnology, A Guide for Students
.
Washington D.C.: American Society for Microbiology,
1996. Print.

Nicholl
, Desmond S. T.
An Introduction to Genetic
Engineering: Second Edition
. Cambridge: Cambridge
University Press, 2002. Print.