Since last summer plasmids sequencing always fails in my lab. We use Zyppy miniprep kit. The other lab using qiagen miniprep kit never have problems. Now we have to PCR our fragment first, and then run DNA gel electrophoresis to cut the gel slice or else we cannot get reading at all. I am so confused about Zyppy miniprep kit. Since it gives a good reading of A260/A280, A260/A230. However, sequencing just don't work. Even for the clones worked before. BTW, We both send our samples to Eurofins Genomics.