9.1 Manipulating DNA
•Set up Cornell Notes on
pg. 17
•Topic: 9.3 DNA
Fingerprinting
•Essential Question:
1. Describe two ways in
which DNA
fingerprinting is used.
9.3 DNA
2.1 Atoms,
Ions,Fingerprinting
and Molecules
1. Describe two ways in which DNA
fingerprinting is used.
KEY CONCEPT
DNA fingerprints identify
people at the molecular
level
Get out your homework:
Who Ate the Cheese?
9.3 DNA Fingerprinting
KEY CONCEPT
DNA fingerprints identify people at the molecular
level.
9.3 DNA Fingerprinting
REVIEW from 9.1
• Gel electrophoresis is used to separate DNA fragments
by size.
– A DNA sample is cut with restriction enzymes.
– Electrical current pulls DNA fragments through a gel.
9.3 DNA Fingerprinting
A DNA fingerprint is a type of restriction map.
DNA fingerprints are based on parts of an individual’s DNA that
can be used for identification.
– based on noncoding regions of DNA that have repeating
DNA sequences
– number of repeats differs between people
9.3 DNA Fingerprinting
X
A DNA fingerprint is NOT actually a
fingerprint!
X
9.3 DNA Fingerprinting
Blood found at crime scene
– Need to determine if it
is the suspect’s blood,
or the victim’s blood
– We can use DNA
fingerprinting to find
out
– The DNA found at the
crime scene belongs
to the suspect
9.3 DNA Fingerprinting
# of repeats
Make a DNA fingerprint (restriction map) based on the
DNA sequence repeats below (p. 16)
7
6
5
4
3
2
1
0
+
9.3 DNA Fingerprinting
Make a DNA fingerprint (restriction map) based on the
DNA sequence repeats below (p. 16)
9.3 DNA Fingerprinting
Make your own DNA Fingerprint! Quick Online Lab
• http://www.pbs.org/wgbh/nova/education/body/createdna-fingerprint.html
9.3 DNA Fingerprinting
DNA fingerprinting is used for identification.
• DNA fingerprinting depends on the probability of a
match.
(mother) (child 1) (child 2) (father)
– Many people have the
same number of
repeats in a certain
region of DNA.
– The probability that two
people share identical
numbers of repeats in
several locations is
very small.
9.3 DNA Fingerprinting
Children
share
some
bands with
both
parents
9.3 DNA Fingerprinting
DNA Fingerprinting Video
2m25s
9.3 DNA Fingerprinting
– Individual probabilities are multiplied to find the
overall probability of two DNA fingerprints randomly
matching.
1 x 1 x 1 =
1
= 1 chance in 5.4 million people to
500 90 120
5,400,000 have the same DNA fingerprint
1 in
every
500
people
has 3
copies in
location
A
1 in
every 90
people
has 6
copies in
location
B
1 in
every
120
people
has 10
copies in
location
c
– Several regions of DNA are
used to make DNA fingerprints.
9.3 DNA Fingerprinting
• DNA fingerprinting is used in several ways.
– evidence in criminal
cases
– paternity tests
(Who da’ Daddy???)
– immigration requests
– studying biodiversity
– tracking genetically
modified crops
9.3 DNA Fingerprinting
The Killer’s Trial
6m30s
• Read the Article
• Watch the video and answer the questions
Who Killed Sally Parker?:
Gel Electrophoresis
A DNA Fingerprinting
Simulation
Today’s Task
Today you will work with a partner to perform a lab simulation
based on a scenario in which you are to identify the murderer
of Ms. Sally Parker.
This activity will model the processes of gel electrophoresis
and DNA fingerprinting
Let’s get started!!
Procedures
• Begin by reading the scenario and
discussing it with your partners. Be sure
you understand the problem.
• Get the materials needed to complete the
activity.
Procedures
•
Following base pairing rules, please fill in the
complementary strand of DNA
•
Examine each DNA fragment strip closely, looking for the
sequence AATT. This is a restriction site, where
enzymes will cut the DNA into even smaller fragments.
Use a pencil to mark these sites, with a line between the
inner A and the inner T (AA│TT).
•
Then use the scissors to cut across the fragments at
those sites. Count and label the number of base pairs
contained in each of the DNA fragments.
•
Use the chart paper provided by your teacher to make a
larger version of the gel electrophoresis chamber.
•
Use a ruler or meter stick to make sure all of the lengths
are the same.
Who Killed Sally Parker?
Materials Needed:
• Direction Packet
• Pencil
• Scissors
• Ruler
• Chart Paper
• DNA Samples (7)
• Tape
• Bio Book (266-267)
Remember to include on your poster:
• Charge (+/-)
• Title
• Color
• Circle the suspect who killed Sally Parker
REMEMBER to cut @ AATT
20
AA TT