My problem: I need to recombine a BAC with a targeting vector and I get clones that do not look entirely correct. After electroporation of the targeting vector into EL250 bacteria containing the BAC I get many clones, but when I digest them they have 1 or 2 large bands like blobs at 4kb or 2kb, even though the first high bands look correct. I have a nice digestion pattern with my original BAC. What are these blobs that cause me so much pain!
I really desperately need help....
