Cloning problem

E Patterson epatters at
Sun Nov 10 22:37:53 EST 2002

If you're using just a a run of the mill plasmid, my first guess is
you're REALLY not supposed to try to stick a 14kb insert into a 4kb
plasmid.  From what I recall plasmids generally can only handle <7kb. 
Read the plasmids manual and it will probably say in the intro what the
maximum size is.  You'll probably need a cosmid for something that's
14kb.  I've not ever worked with them before though because I've never
stuck more than 2kb into a plasmid.

dygibbs at wrote:
> I have attempted to clone a 14 kb insert (Mlu I/Xho I) into a 4 kb vector (Mlu I/Xho I).  The vector has been gel purified and dephosphorylated (shrimp alkaline phosphotase), the fragments ligated (NEB T4 ligase overnight at 16 C), and transformed into XL-1 supercompetent cells (Stratagene).   After plating/overnight incubation, very few colonies are present, and after screening for positives with Mlu I/Xho I, there is no insert.  Any suggestion/tips?

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