Download 9.3 DNA Fingerprinting

9.1 Manipulating DNA
•Set up Cornell Notes on
pg. 15
•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
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
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
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
DNA Evidence Video
No Electronics At School!
Who Broke The Rule?
Gel Electrophoresis
A DNA Fingerprinting
Simulation
Today’s Task
Today you will work with 2 partners to
perform a lab simulation based on a
scenario in which you are to identify
the owner of an electronic device left
in a classroom and subsequently
claimed by four different students.
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
• 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.
Use “Who Ate the Cheese” as a model
Who Broke the Rule?
• Materials Needed:
– Scissors
– Ruler
– Chart Paper
– DNA Samples (5)
– Glue Stick
– Bio Book (266-267)
– Charge (+/-)
– Title
– Color
– Circle the person who broke the rule!!!!
REMEMBER to cut @ CCGG
16
CC GG
Procedures
• Examine each DNA fragment strip closely, looking
for the sequence CCGG. 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 C and the inner G (CC│GG).
• 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.
• Look at each DNA fragment carefully, looking for
the sequence CCGG. This is a restriction site,
where enzymes will cut the DNA into even smaller
fragments.
• Count and label the number of base pairs
contained in each DNA fragment.