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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
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
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
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.