When the band is short, there are less EB (or other dyes) that can be combined, so the brightness of a relatively long section is very weak, and it is difficult to see when it is less than 500.

Solutions, basically all mentioned upstairs:

1. Increase the concentration of agarose gel to 2%-3%.

2. Run a single restriction control. If there is a difference, it means there is correlation. However, if the target fragment is to be recovered, it is suggested to use sequence PCR amplification on the vector, and it is not easy to recover DNA less than 400bp. 5. Increase the gel concentration. 2. Run a gradient of 5 10 15ul with 2% agarose gel.

It is recommended to run after PCR, because the enzyme cut may be too low.

Sepharose resolution is poor, 0, is it marked? Just look at the marker. Maybe it's used up. . . Why can't I see my target band after 0, 1% agarose electrophoresis?

My target band is 177bp. After the plasmid was digested by double enzymes, the target band could hardly be seen by electrophoresis. Is it because the target band is relatively small, running in front is easy to blur and the brightness is weakened? Double enzyme digestion is a 20ul system, and 8ul is used for sampling. After enzyme digestion, the large band is clear, and my target band 177bp is almost invisible. I don't know why.

Of course, markers are added. I haven't used it up yet ~ but thank you for your answers.