was collected in a 1 5 ml eppendorf tube and 500 u03bcl ctab buffer 65 u00b0 c see below were added the mixture was incubated 1 to 1 5 h at 65 u00b0 c and subsequently centrifuged for 5 sec 5 u03bcl rnase a 10 mg ml were added the mixture was incubated 30 min at 37 u00b0 c and subsequently centrifuged for 5 sec 200 u03bcl sevag were added after mixing and centrifugation at 13 000 rpm for 10 min the supernatant was transferred to a new 1 5 ml tube 1 volume isopropanol about 400 u03bcl was mixed carefully with the supernatant a centrifugation step at 13 000 rpm for 10 min followed 600 u03bcl 70 ethanol were added the pellet was washed by inverting the tube several times again the mixture was centrifuged at 13 000 rpm for 2 min the ethanol was carefully discarded the tube was inverted and drained on clean paper the sample was allowed to air dry for 15 min the pellet was redissolved in 50 u03bcl h 2 o see below 5 ml bidest 50 mg rnase a aliquots in 1 5 ml tubes boil tubes 30 min at 100 u00b0 c storage at u2212 20 u00b0 c.