phenol/chloroform extraction
1. add equal volume of phenol/chloroform/isoamyl alcholo (25:24:1)
2. shake by hand
3. spin 2 min at max speed
4. carefully extract aqueous phase (top) containing DNA
5. add 2.5 volumes EtOH and 0.1 volume 3M NaAc pH5.2
6. mix
7. freeze for > 20 min
8. spin for 10 min in cold room.
9. discard supernatant.