Below are some frequently asked questions about our DNA Sequencing services. Should you have any questions other than listed below, feel free to contact us at sequencing@biobasic.com and we will be happy to clear your thoughts.
We would need you to first clearly tell us at which position is unclear to you and then we would go case by case.
Yes. However, please note, all sequencing results are kept for a period of 6 months. Samples are kept at Bio Basic Inc. for 1-2months.
For PCR >2kb, we recommend to first subclone into a vector. The insert is more stable in a vector and sequencing results will be easier to achieve.
When preparing the report, Bio Basic Inc. assumes each sequencing sample is from a pure single population rather than mixed. Based on this assumption, the higher/stronger peak is being reported and lower/weaker peak being treated as background. If your sample contains a mixed population, please kindly notify us.
If you see this, you usually have two sequences superimposed on each other. There are several common causes:
Secondary structure in the template is the most likely cause of this problem. The polymerase is presumably unable to progress through some stem-loop form. A few possible solutions:
We maybe able to use special cycling conditions and/or special reagents that help the polymerase to push through this region. We cannot do this routinely, as it involves extensive optimizations.
This usually happens when the template DNA has simply stopped, for example if it was restricted at a downstream site or if the template was a PCR product. This may also be caused by an extremely stable secondary structure.
This is called "polymerase slip". It happens when the growing strand temporarily dissociates from the template, then reassociates at a different spot - say, one nucleotide forward or back from where it started. If this happens often enough (as it will on polyA or polyT templates), every individual band becomes a family of closely-spaced peaks giving a 'roller coaster' look to the chromatogram. Try sequencing in the other direction from the opposite strand, or try another primer either closer or further from the homopolymer region.
24hr to 48hr is AFTER we receive the samples at Bio Basic Inc. If you have more than 5 plates, longer turnaround is expected.
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