Any standard mini-prep method is suitable. Below is the method used in-house at Geneservice Ltd.

1. Streak out cosmid onto LB + kanamycin plate. Incubate overnight at 37º C.
   
   
2. Dispense 5 ml LB medium into a 50ml sterile tube. Add 5 µl kanamycin ( 30 mg/ml). Inoculate with a single colony and incubate overnight in shaking incubator 37º C /170 rpm.
   
   
3. Transfer aliquot of 140 µl to a 1.5ml microtube. Add 40 µl 80 % glycerol.
   
   
4. Centrifuge 15 min 3000 rpm.
   
   
5. Pour off supernatant and discard. Re-suspend pellet in 200 µl GTE.
   
   
6. Lysis: Add 400 µl 0.2 M NaOH/1% SDS (freshly made). Mix by inversion. Place on ice for 30 min.
   
   
7. Add 300 µl 3M K Ac. Invert to mix. Place on ice for 30 min.
   
   
8. Add 10 µl RNAase A stock (10mg/ml). Incubate 10 min 37ºC.
   
   
9. Centrifuge 10 min at 13000 rpm in microfuge. Decant supernatant into a 1.5ml microtube containing 1 ml cold ethanol, vortex briefly and leave to stand for 1 min.
   
   
10. Centrifuge 10 min at 13000 rpm in microfuge. Remove ethanol carefully (preferably by suction technique).
    
    
11. Add 200 µl cold 70% ethanol, vortex briefly, centrifuge 10 min at 13000 rpm in microfuge, remove ethanol carefully (as above).
    
    
12. Air dry pellet. Add 50 µl TE and leave to re-suspend overnight at 4°C.

Solutions:

GTE (10 ml) :

0.5 ml 20% glucose
0.25 ml 1M Tris/HCl pH 7.5
0.2 ml 0.5M EDTA pH 8.0.
9.05 ml sterile distilled water

Lysis Buffer (100 ml 0.2M NaOH/1% SDS):

0.8 g NaOH
5 ml 20% SDS
95ml sterile distilled water.

19^thJanuary 1999 Version 1.1