焦磷酸测序仪常见问题及解答

2875 - What is the reason for signals ceasing in the middle of a pyrosequencing run?

The cartridge needle can be blocked or damaged causing a dispensation error. Clean the cartridge following the guidelines or repeat the run with a new cartridge. On the other hand if high amounts of template have been used resulting in very high signals (>100 RLU), the substrate for the sequencing reaction might be depleted. In this case template conditions should be optimized.

2879 - What is the reason for a high substrate peak in the pyrosequencing pyrogram?

Usually pyrophosphate or dATP/ATP contamination in the sample or in the buffer can cause a high substrate peak. Large amounts of pyrophosphate are generated in the PCR reaction and might be carried over to the sequencing reaction. Check the PyroMark buffers and reagents and use new ones.

2871 - How many nucleotides of a homopolymer can be resolved in pyrosequencing?

In the range of 3-5 bases can be resolved depending on the sequence context and base. If it is possible sequencing of a homopolymer of more than 3-5 nucleotides should be avoided by resetting the sequencing primer.

2870 - What does it mean when I get a "wide peak" error appearing at the end of a pyrosequencing run?

Usually wide peaks result from too much template for the used enzyme/substrate activity, or from reduced activity/performance of the enzymes themselves so that the pyrophosphate from previous nucleotide incorporation cannot be degraded as fast as usual. 2881 - What is the reason for split peaks appearing in between dispensations on my pyrosequencing pyrogram?

The PyroMark cartridge needle can be blocked or damaged. Clean the cartridge or exchange with a new one. Check for correct reagent cartridge and cartridge method used in the run. Check if the reagent cartridge cover was closed properly. Make sure that the cartridge was dry after cleaning because nucleotide droplets might be caught at the needle tip and fall down at any time. or exchanged.

2878 - How do I prevent a drifting baseline in my pyrosequencing pyrogram?

Let the PyroMark instrument warm up (about 60 minutes) to adapt to room temperature before use. Make sure the ambient room temperature is within range 18-28°C.

2877 - How do I reduce background peaks in the pyrosequencing pyrogram?

There are several reasons for a high assay background; the template can form secondary structures which are extended or the primers itself form dimmers which serve as template. Perform accurate sequencing controls (e.g. PCR or sequencing primer only) as recommended in the PyroMark User Manual to observe this kind of background. In addition, an unspecific priming of primer to template or unspecific annealing of sequencing primer to template might also be a background cause. Please check your complete primer design and if needed, perform a redesign. Try to lower the primer concentration as possible to avoid excess of primer. 2876 - What is the reason for low peak signals in pyrosequencing?