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Star Republic: Guide for Biologists

Isolation of genomic DNA from mouse tails

1. Put a 0.5-1.5 cm mouse tail snip in a 1.5 ml eppendorf tube and store frozen util digestion. Tails should never be left at room temperature.

2. To each tube, add 500 ml of tail prep solution:

50 mM Tris-HCl pH8.0
100 mM EDTA
100 mM NaCl
1% SDS
0.5 mg Proteinase K/ml

3. Make sure the tails are submerged. Digest at 55 C overnight.

4. Cool samples on the ice. Add 0.5 ml phenol, mix, and spin 12,000 rpm x 10 minutes at room temperature.

5. Transfer the aqueous phase to a new eppendorf tube. Add 0.5 ml phenol:chloroform:isoamyl alchol (25:24:1), mix, and spin 12,000 rpm x 10 minutes at room temperature.

6. Repeat Step 5 with 0.5 ml chloroform.

7. Transfer the aqueous phase to a new eppendorf tube, add equal volume 95% ethanol. Gently invert the tube several times to precipitate DNA.

8. Centrifuge 10-15 minutes at 12,000 rpm.

9. Remove the supernatant, wash pellet with cold 70% ethanol.

10. Dry the pellet. Don't over dry since genomic DNA may stick to the eppendorf tube permanently. Resuspend pellet in 200-400 ml TE.