Sounds like you have a contamination with pBluescript. Somewhere
somehow, I get that often. I usually do PCR colony screen to get the
right construct, using a P vector-specific primer together with one in
Chris Jones <6kuritaro at earthlink.net> wrote in message news:<6kuritaro-CD5F10.20302503042003 at nnrp02.earthlink.net>...
> Hi there --
>> I'm hoping someone has an explanation (or even better, a solution) based
> on experience:
>> My student is trying to subclone a 4.1 kb Xba fragment into pCaSpeR-hs
> (ca. 8.8 kb) in preparation for egg injections. The problem is that when
> we ligate and transform bacteria, the resulting plasmids are either just
> recircularized vector (no surprise there) or uniformly too small -- each
> of these consists of a 4.1 kb fragment and a (roughly) 2.7 kb fragment
> when re-cut with Xba. What's happened to the pCaSpeR-hs?
>> The insert has already been subcloned into another vector, so it seems
> to be tractable. Has anyone ever run across something like this? We've
> tried this several times, always with the same results. As you can
> imagine, it's very frustrating (especially for my student).
>> Thanks for any advice.