Genomic Library Screening

Warren Gallin wgallin at
Mon Feb 28 10:38:08 EST 1994

In Article <1994Feb26.213031.1903824 at>,
ZACHARIAS at Meena.CC.URegina.CA (Tracey Zacharias) wrote:
>I am screening a lambda genomic library and think I have some positives.       

>I have picked them, grown them up in LB + E.coli and now want to screen
>them again.  I am thinking of just taking about 5 microL and dotting 
>it on a membrane and then treating just as if I had done a plaque 
>lift.  Is this a reasonable approach?  I cannot find any references 
>that do it this way.  Does the LB that the lambda was grown up in have
>an effect? Will I get a bunch of positives that aren't really positive 
>due to LB?  
   If you have plaque purified the phage, what you are proposing is
redundant.  If you haven't plaque purified, then you need to replate from
your stab and get a single positive plaque.
   What I usually do once a clone is plaque purified is to purify some of
the DNA and do a Southern blot.  You need the information anyway, and you
will be confirming that the hybridization is to a specific DNA fragment.
Warren Gallin,
Department of Zoology, University of Alberta
wgallin at

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