1)UsePharmacia#27-4564-01.Withcleanflamedscissorsandforceps,weigh0.25g/50mlconicalandadd50ml/conicalof0.02MTris,pH7.6.Allowtodissolveoverseveraldaysat4°C. 2)Vortex.Drawupintoa20or30mlsyringe.Adda25guageneedleandshearDNAbysquirtingthroughneedleintofresh50mlconicalsat15ml/conical.Tothisadd0.9ml/conicalof5NNaCl. 3)Boilinwaterbath(95-100°C)for20min.Coolinicewater.Vortexandthenadd1drop(fromastandardtransferpipet)of1.2NHCl(concentratedHCldiluted1/10)toneutralize. 4)Addtwovolumesof100%ethanol,letstandfor20minonice,thenspinfor10minintheBeckmanGS-6Rat2500rpm(4°C).Pouroffthesupernatant,letdryfor5min,thenadd15ml/tubeof0.02MTris,pH7.6.Vortexandletdissolveforseveraldaysat4°C.DetermineOD260ofadilutedaliquottocheckconcentration(1OD260=50µgDNA/ml),thenstoreat-20°C.PreparationofSonicatedSalmonSpermDNA
