southern enigma

[William Sun]

Hello all,

I have a 600bp DNA fragment which I cut out of a plasmid, purified from agarose
gel with Gene Clean and labeled with 32P using random prime method.  I then
used the probe to screen a lamba ZAP cDNA library (Stratagene) and 
isolated several clones.  I isolated the clones and cut the inserts out for
a southern blot.  I then hybridized the blot with the same 600bp probe.  To my
surprise, I don't see any signals on the inserts.  Instead, I see signals
representing the 3 kb Bluescript vector and the bands in the 1 kb ladder!
Anyone can think of an explanation?

William

-- 
William Sun, Ph.D                      Phone: (619) 622-3930
Metabasis Therapeutics, Inc.           FAX:   (619) 622-5545
9390 Towne Centre Drive                Pager: (310) 243-9878
San Diego, CA 92121                    http://rana.usc.edu:8376/~wisun/