Genes in a Bottle

Protocol Highlights

What can you teach with the DNA Extraction Kit ?

• Reinforce the structures of a cell

• Introduce procedures involved in DNA extraction

• Preserve student DNA samples

What do you need to do Genes in a Bottle?

Step 1

• Label 15ml tube containing water with your initials

• Gently chew the inside of your cheeks for 30 sec

• Put the water in your mouth and swish for 30 sec

• Expel the liquid back into the 15ml tube

Collect cells

Step 2

• Add 2 ml of lysis buffer into your tube

• Cap your tube

• Gently invert the tube 5 times, DO NOT SHAKE

Why use Lysis Buffer?

What is in the Lysis Buffer?

50 mM Tris-HCl, pH 8.0Maintains pH at which DNA is most stable

1% SDSBreaks open cell and nuclear membrane

O

S

O

O

O

-

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH3

SDS

Step 3

• Add 5 drops of salt/protease to your tube

• Cap your tube

• Gently invert 5 times

• Incubate at 50ºC for 10 minutes

Why add Salt/Protease?

• DNA has a negative charge. Salt (NaCl) neutralises the charge because the Na ions sheild the negative charge of the phosphate backbone.

• To destroy “DNAses” (proteins) that break down DNA

• To break down histones to unwind DNA.

• To increase the amount of intact DNA obtained

What can we do with the DNA?

• Genetic testing• DNA fingerprinting• Genetic engineering

the Inventor was…

Sir Alec JeffreysGenetics DeptLeicester

University

Cardiff 3

The scene of the crime

Man was charged with murdering Cardiff woman 17 years ago.

Tahini-

The Genetic Donor

Tabouli and Baba Ganoush

The Clones

Step 4

• Hold your tube at a 45ºC angle

• Slowly fill the tube with ICE COLD ethanol (10ml)

• Leave undisturbed for 5 minutes

• After 5 minutes, gently invert the tube

Why add alcohol?

• DNA cannot dissolve in alcohol

• Cold alcohol makes the DNA clump together and precipitate out of solution

• Precipitated DNA molecules appear as long pieces of fluffy, stringy, web-like strands

Transferring DNA into glass vials

Using a plastic transfer pipette, transfer the DNA strands into the amulet

IMPORTANT- put the pipette tip as far as it will go into the amulet or the liquid will not enter

Leave about ½ cm from the top of the neck of the tube to put the stopper back into the amulet

DNA Necklace Preparation

• Push the silicon stopper back into the vial.

• Apply a small amount of Superglue around the rim of the vial and to the inside of the silver cap.

• Twist on the silver cap.

• Hold it down for a few minutes, then allow the cap to dry completely.

• Once the cap is dry, run the cord through the cap and tie it.

Congratulations! You have just made your very own DNA

Necklace !