bedal001 at mc.duke.edu
Tue Apr 25 17:38:58 EST 1995
In article <3njeac$dc8 at mark.ucdavis.edu>, ez022056 at bullwinkle.ucdavis.edu
(Edward Wang) wrote:
> 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.
Is this a TA cloning kit? If so, maybe your vector has lost its T-tails
over time- I know that can happen with the Invitrogen TA cloning vector.
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