Extract your DNA

Aim
To isolate DNA from mouth mucus cells
Advance Preparation
Alcohol solution must be ice-cold, put it in refrigerator or in ice
Safety
Alcohol vapour from 95% concentration can give nausea and dizziness
Organization
This activity will take about 25 minutes from preparation (10 min) to completion (15
min)
Equipments and Materials
250 ml drinking water
1 table spoon of cooking salt (NaCl)
2-5 drops of dishwashing soap
150 ml 70-95% alcohol
1-2 drops of food colouring (pick any colour that you like)
1 transparent plastic cup or test tube
1 eye dropper/ pipette
1 wooden stick (ice cream stick)
Protocols
1. Add the salt to 250 ml to drinking water
2. Gargle with the salty water and spit it out in a new transparent plastic club
3. Add the dishwashing soap
4. Swirl gently or stir it 2-3 times with wooden stick
5. Add 1-2 drops of food colouring to the alcohol solution
6. Add the alcohol solution to the cup
7. Watch the DNA (whitish strings) formed in the middle of two layers of water and
alcohol
What Happened?
The skin cells inside our mouth were easily
removed by gargling and swishing the water in
our mouth. Salty water was used to mimics the
salty fluids inside our body. Once the soap
added, membrane cells break open and release
the DNA. DNA gradually migrates and gets
stuck together (called coiling) and become
visible by naked eye. Isn’t it amazing to see
these small molecules build up living
organisms?