1. Obtain tail biopsies from 2 to 3 week old mice: Hold mouse firmly at base of tail with one hand, with the other cut off 0.5 to 1.0 cm of the tail tip with a scalpel or single edge razor blade.

2. Add 600 microliters of TNES and 35 microliters Proteinase K (10 mg/ml).

3. Incubate overnight (8-24 hr) at 55 degrees C.

4. Add 166.7 microliters 6M NaCl. Shake vigorously for 15 sec.

5. Microfuge (12,000-14,000 xg) for 5 min at room temp.

6. Remove supernatant to new tube and add 1 volume cold 95% ethanol (EtOH).

7. Spool precipitated DNA with closed end capillary tube.

8. Rinse DNA pellet with 70% EtOH (dipping in a tube filled with 70% EtOH works well) and allow to air dry 5-10 min.

9. Resuspend in 100-500 microliters of TE (10mM Tris, pH 8.0, 1mM EDTA). Volume depends empirically on pellet size.

10. Heat at 65 degrees C for 10 minutes to aid dissolution of DNA.

11. Quantitate DNA and store at 4 degrees C until needed.

TNES
10 mM Tris, pH 7.5
400 mM NaCl
100 mM EDTA
0.6% SDS

"6M" NaCl
Saturated salt solution stored at 37° C

Miller SA. Dykes DD. Polesky HF. 1988. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Research. 16(3):1215.