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.

2.1 Atoms, Ions, and Molecules

9.3 DNA Fingerprinting

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

A DNA fingerprint is NOT actually a fingerprint! XX

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

Make a DNA fingerprint (restriction map) based on the DNA sequence repeats below (p. 16)

-76543210+

# of

rep

eats

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/create-dna-fingerprint.html

9.3 DNA Fingerprinting

DNA fingerprinting is used for identification.

• DNA fingerprinting depends on the probability of a match.– Many people have the

same number ofrepeats in a certainregion of DNA.

– The probability that two people share identicalnumbers of repeats inseveral locations isvery small.

(mother) (child 1) (child 2) (father)

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.

– Several regions of DNA are used to make DNA fingerprints.

1 1 1 1500 90 120 5,400,000

1 chance in 5.4 million people to have the same DNA fingerprint

x x = =

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

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 ElectrophoresisA DNA Fingerprinting

Simulation

Today’s TaskToday 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

20REMEMBER to cut @ AATT AA TT