I.Protocol1.HarvestcellsOptional:washplatewith37°CPBS(gently,soasnottolosecells);checkonmicroscope,afteraspiratePBSormediaPlaceplateoniceLysewithDNAladderbuffer4°C150ul/60mmplateScrape,transfertoEppendorfRotate4°C20min2.Microcentrifuge15min,4°CTopelletchromatinTransfersup3.Phenol/CHCl3extractAddequalvolumephenol/CHCl3MixbypipettingMicrofuge2min;transfersupWilloftengetaverylargeinterface4.Optional:re-extractorganicAdd300-500ulTE8.0;mix;spin;poolsups5.EthanolPrecipitateIneppendorftubeor15mltube,dependingontotalsupvolumeAdd1/10vol.3MNaOAcetate,2vol.ethOH–20°Covernight6.RecoverDNACentifugeEtOHppt:Ifin:15mltubes:SorvallSA600,8,000RPM,10min,4°Cepptubes:microfuge15min,4°CIfwasin15mltube,probablybesttoresUSPendinsmallvolume(e.g.,500ulTE),thenre-EtOHpptinepptube,sopelletwillbetight80%EtOHwash:add≈500ul;vortex;re-spinSpeed-vacdryResuspendinTE8.0:≈25ul/eppendorf;roomtemp≈30min7.RNaseAdd1ul1ug/ulRNaseA;roomtemp30min8.GelelectrophoresisAdd5XloADIngbuffer(*omitbromophenolblue:caninterferewithbandvisibility;maybeOKtoaddxylenecyanol)Runon1.2%agarosegel,inTAEbufferII.ReagentsDNALadderingBuffer:40ml0.5%TritonX-100800ul25%5mMTrispH7.4200ul1M20mMEDTA1.6ml500mM37.4mldH2OIII.NotesReference:Hockenberryetal.Nature