Hi all,

I did in-fusion cloning trying to insert some fragments into a 7kb vector. After transformation and isolation of plasmid, I conducted test digestion using enzyme XbaI and ran positive controls (the original vector cut by XbaI).

• If insertions were successful, XbaI digestion should give 3 bands: 875, 1204, 8321 bp;
• If failed, empty plasmids should give 7kb;
• The positive control should give 7kb

However, the positive control showed a different size band from those isolated after transformation. Does anyone know what's wrong with this? And I'm pretty sure the original plasmid size is 7kb, it's copies from commercial products. I confirmed the size by electrophoresis and digestion. Here it looks like it's at 10kb, it's because the ladder of 10 and 8 are close, and the gel hasn't run long enough.

Hope someone can help explain this issue. Thank you so much!