This document provides instructions for extracting DNA from saliva at home. It explains that DNA can be found inside cells in the nucleus and is packaged into chromosomes. The procedure involves swishing mouthwash to collect cheek cells, spitting into a solution of water and detergent to lyse the cells and release DNA, then adding cold alcohol which causes the DNA to separate out and form white strands or clumps visible at the top of the mixture. With patience, one can isolate their own unique DNA through this simple at-home extraction process.

1. Kohtla-Järve Slaavi Põhikool
Julia Kropatševa, Julia Golosova
Ilona Kekla
20.05.2013
DNA Extraction
in

2. What does DNA mean?
Deoxyribonucleic acid
(DNA) is a molecule that
encodes the genetic
instructions used in the
development and
functioning of all known
living organisms and many
viruses

3. Where is DNA located?
DNA is found inside a special area of the cell called the nucleus.
Because the cell is very small, and because organisms have
many DNA molecules per cell, each DNA molecule must be
tightly packaged. This packaged form of the DNA is called a
chromosome.

4. Where is DNA located?
Any body consists of different organ systems ( digestive,
breathing and so on). The system consists of organs. The
organ consists of materials, and any materials – of a cell.

5. Welcome
to

7. Procedure

10. O Swill out your mouth with the saline solution for about 30 seconds. This is to
collect the DNA contained in your saliva, and around the walls of your cheeks.
You can also extract DNA from blood, hair, skin or even semen too, but the
techniques for obtaining these types of samples are more difficult to do at home
without more complex equipment (although perhaps slightly more interesting in
their collection).
O Spit the contents of your mouth into a glass containing a mix of three
teaspoons of water and one teaspoon of washing-up liquid/detergent. You are
thus (hopefully) transferring the DNA from your cheek cells into the solution.
O Stir this mix slowly and gently (scientists use the fancy term 'mechanical
agitation') for a couple of minutes. During this process it is necessary to break up
tissue (in this case, cheek cells) mechanically, and then to degrade both the cell
membranes and those surrounding the nuclei - releasing the DNA contained
within them3.
O Now pour (slowly!) some of the ice-cold alcohol carefully down the inside of
the glass, allowing it to settle on top of the solution. DNA is insoluble in cold
alcohol and while there will be a few bubbles, the other compounds in the
mixture will dissolve, and the DNA will separate from the other ingredients.
Leave it for about two to three minutes for this to happen4.
O If you are lucky you will see a spindly white substance, maybe clumps of it if
you are really careful, forming on top of the salt/detergent mixture. Be patient - it
will happen slowly. The resulting 'goo' is unique to you; it is your very own DNA!5

11. The DNA Song

14. O http://www.genome.gov/25520880
O http://h2g2.com/approved_entry/A265604
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