blue colonies

Edward Wang ez022056 at bullwinkle.ucdavis.edu
Tue Apr 25 13:16:44 EST 1995


I am currently doing PCR cloning using the Promega pGem-T system.  
Everything was working fine, and I was getting several hundred : 5 White 
to blue ratio, using Stratagene's super competent (10^9 efficiency) XL1 
Blue cells.  Because of the high cost, I switched to Promega's JM109 
(10^8 efficiency).  Now, my plates have lots of blue colonies : very few 
white colonies.  Does anyone know any explaination for this?
Also, we are trying to od Nrothern blots with probes made from 
differentialy displaying fragments (DD-RTPCR), but so far with no luck 
(nothing shoing on the blot).  Has anyone else had any similar problems, 
and perhaps even the solution to the problems?  Thanks in advance.

--
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Edward H. Wang                 *
Staff Resch. Assc.             *
Dept. Internal Med. -Nephrology*
UC Davis                       *
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