I have a quick question about pJET1.2 that I could use some help in. I know it is linearized and phosphorylated at the 5' so why doesn't it re-ligate back together immediately when ligase is added? I know it distrupts a lethal gene, so I would think that if someone tried to insert a blunt PCR product, pJET would ligate to itself (energy favorable) first and not allow insert a chance to "get in there". Thus creating a lethal product. I know this doesn't happen because we use it in lab, but I was curious.
Any insights would be appreciated!