Duplex DNA is isolated from bacteriophage lambda (cI857ind 1 Sam 7)

Lambda DNA is 48,502 base pairs in length. The phage is isolated from the heat-inducible lysogen E. coli l cI857 S7. The DNA is isolated from the purified phage by phenol extraction and dialyzed against 10 mM Tris-HCl (pH 8.0), 1 mM EDTA.