dna extraction

[archna singh]

my protocol for genomic DNA extraction is exactly as follows. PLEASE  point
out sources of error ive repeated this process five times now using fresh
reagents for each step.
                            cell pellet/ tissue(5-15mg)washed with 0.1%
STE(pH 8.0),incubated at 37 degrees for 15 minutes,proteinase K added for
overnight incubation at 37 degrees,followed by 5 molar sodium chloride for
30 minutes followed by PCI extraction(in ratio of 25 is to 24 is to 1)
followed by chloroform extraction followed by addition of 0.6 volumes of
isopropranol followed by overnight extraction followed by pelleting down
of   DNA followed by washing with 70% ethanol ND DRYING . THEN SUSPENDED IN
TRIS EDTA OVERNIGHT. OD TAKEN AT 260/280. PLEASE HELP..


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