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.

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

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

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

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

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!!!!

16REMEMBER to cut @ CCGG 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.