Dear Chunxin Wang,
If you use the Dam+ E. coli,
A of GATC is methylated.
So the Cla I site of gATCGAT will be blocked
by dam methylation.
>>Does anybody know if the BAC DNA is methylated or not? One of my labmates
>is trying to subclone one BAC into a binary vector. He cut the BAC with
>Cla I, but it does not give rise to the right predicted digestion pattern.
>He suspected that some sequences around Cla I sites has been methylated.
>Is it true?