1. Grind 20-50 frozen flies with a mortar and pestle in N2(l) and suspend in 2 ml Lysis Buffer.

2.Add Proteinase K to 100 mg/ml; incubate 1-2h @ 37℃ with occassional swirling.

3. Phenol extract GENTLY, 10'; cfg. 5' @ RT. Harvest the aqueous phase with a large bore transfer pipet.

4. Phenol-Sevag extract 1X; Sevag extract 1X.

5. Harvest the aqueous phase and precipitate the DNA with 0.5 vol 7.5M NH4OAc + an equal vol isopropanol; mix gently.

6. Spool out the DNA (or leave to ppt. ON @ -20℃), rinse in EtOH and air dry briefly before resuspending in TE.

7. Digest the DNA with pretreated RNase A @ 100mg/ml; 37℃, 30'.

8. Phenol-Sevag extract 1X; Sevag extract 1X.

9. NaOAc/EtOH ppt.

10. Resuspend GENTLY in TE-4.

Lysis Buffer 50 mls:

100 mM Tris-HCl, pH 8 5.0 ml 1M Tris-HCl

50 mM NaCl 0.5 ml 5M NaCl

50 mM EDTA 5.0 ml 0.5M EDTA

1 % SDS 2.5 ml 20% SDS

150 mM Spermine 75 ml 100mM Spermine-HCl4

500 mM Spermidine 50 ml 500mM Spermidine

36.875 ml ddH2O

TE (10 mM Tris-HCl, pH 8/1 mM EDTA)

TE-4 (10 mM Tris-HCl, pH 8/0.1 mM EDTA)

acc 1/90