DNA Fingerprinting

Get your safety glasses

Sit next to a partner

DO NOT OPEN ANY BOXES YET PLEASE

LEGO Model of DNA

• DNA is a molecule in your body.

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• It is a code, which stores instructions for building the “machines” in your body.

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• It is a double helix.

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• It is a millionth of a millimeter wide.

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• In humans, a molecule of DNA is 200,000,000 bases long.

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DNA is a Code

GGAAAACTAAC

CCTTTTGATTG

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• The genetic code is written in A’s, T’s, C’s and G’s.

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• The sequence of A’s, T’s, C’s and G’s uniquely identifies a person, unless they are a twin.

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• That’s why it’s called DNA fingerprinting.

Restriction Enzymes are Molecules that Cut DNA at Particular “Words”

Restriction Enzyme Cuts Yield Different Sized DNA Fragments

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Gel Electrophoresis is Used to Separate the Fragments Based on Size

Gel Animation

How to do DNA fingerprinting

Example DNA Fingerprint

• Column in Gel corresponds to a person’s DNA.

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• It is called a person’s DNA fingerprint.

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• Row corresponds to DNA fragment size.

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Different People Have Different Restriction Enzyme Cut Sites

Resulting in different band patterns on a gel.

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Resulting in different sized DNA fragments.

DNA �Fingerprinting Real World�Applications

• Crime scene

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• Human relatedness

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• Paternity

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• Animal relatedness

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• Anthropology studies

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• Disease-causing organisms

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• Food identification

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• Human remains

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• Monitoring transplants

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Solving a Murder Mystery Using DNA Fingerprinting

Who did it?

Solving Our Murder Mystery Using DNA Fingerprinting

Given crime scene DNA and suspect DNA you will construct a gel.

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You will then analyze the gel to find a match between the crime scene DNA and a suspect’s DNA.

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You will use this information to make inferences about the murders.

Great Migration Project Science

On the back of the page answer # 9-11

write which DNA sample tube you have

Give a purpose on why DNA fingerprinting may be used

Write your hypothesis: If I do a DNA Fingerprint Analysis then my family genealogy will be from________________ (give me which state)

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Reminder the options are: South Carolina

North Carolina

Georgia

Mississippi

Alabama

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These are the states with the greatest emigration from the south to the north during the Great Migration

DNA Fingerprinting

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Preparing Agarose Gels

for Use with

Carolina Blu

Agarose Gel Prep�Step 7

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• Pour into a 250 ml flask or beaker 45 ml of 1X TBE electrophoresis buffer prepared in steps 5 and 6.

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DNA Fingerprinting

Agarose Gel Prep�Step 8

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• Add 0.7 g of agarose to the 1X TBE and swirl to disperse the powder.

DNA Fingerprinting

Agarose Gel Prep�Step 9

• Microwave the suspension until it boils (about 30 seconds to 1 minute). Swirl the flask and alternate boiling and swirling at 15 second intervals until the solution has boiled a total of 1 minute or until there are no visible solids.

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DNA Fingerprinting

Agarose Gel Prep�Step 12

• Place a comb(s) of choice into the tray slot.
• Slowly pour the agarose solution into the gel tray, taking care not to allow formation of any bubbles within the gel.

DNA Fingerprinting

As we wait

Practice using the pipettors with the ORANGE practice loading dye

https://www.youtube.com/watch?v=NGJ5spD8Evk

https://www.youtube.com/watch?v=FkamMDRVoz8

Agarose Gel Prep�Step 13

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• Allow the gel to sit at room temperature for about 30 minutes until solid (gel will appear slightly milky).

DNA Fingerprinting

DNA Fingerprinting��Agarose Gel Electrophoresis��Student Instructions

Agarose Gel Electrophoresis �Step 1

• Use the pipettor to add 4 µl of migration dye from tube "D."
• Make sure to change tips after each use.

DNA Fingerprinting

Student Instructions

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Agarose Gel Electrophoresis �Step 2

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• Using a pipettor set at 20 µl, transfer the sample into the appropriate lanes of the gel.
• Make sure to change tips after each use.

DNA Fingerprinting

Student Instructions

Write down the order in which you are loading the gel on number 12

IMPORTANT VERY IMPORTANT!!!

Agarose Gel Electrophoresis �Step 3

• After the samples are loaded, slowly fill the gel box with the 1X TBE buffer. Make sure the gel is completely covered.
• If there is not enough buffer, add distilled water to finish covering the gel.

DNA Fingerprinting

Student Instructions

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Agarose Gel Electrophoresis �Step 4

• Turn the switch on the power supply to "Off" before connecting the electrophoresis chamber.
• Place the lid tightly on the chamber and plug the electrical leads into the recessed output jacks of the power supply.
• Plug the red (+) lead into the red jack, and the black (-) lead into the black jack.

DNA Fingerprinting

Student Instructions

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Agarose Gel Electrophoresis �Step 5

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• Select the desired voltage on the power supply. A voltage of 150 will permit the electrophoresis run to be completed in about an hour.

DNA Fingerprinting

Student Instructions

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Agarose Gel Electrophoresis �Step 6

• Turn the power supply switch "ON." The blue migration dye should move toward the positive electrode (red). If it is migrating toward the negative electrode (black), turn off the power supply, remove the lid, turn the gel tray 180^o, replace the lid, and turn the power supply "ON."

DNA Fingerprinting

Student Instructions

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As We Wait

Answer #1-8 on the front of the sheet.

Now draw a picture of how your gel looks.

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Turn your paper sideways so the wells are at the top of the picture.

Looking at your gel, draw a line in each approximate location you see on your gel as shown in the video as well as the pictures in this slide.

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Now answer REE, PE, PA.

Look at the gel. Which of the states matched your sample. That is where your ancestors emigrated from. So answer REE about your hypothesis (#11) and HOW you know. (what did you look for in the gel)

PE- We all make mistakes- here is one that my group and/or I made. AND this is how it may have affected my results

PA- How can DNA fingerprinting can be used outside of a genealogy test.

TURN IN YOUR PAPER