Quantification of CpN methylation
The new CpN mode of PyroMark Q24 Advanced now enables methylation analysis of cytosine residues that are not part of CpG sites. Analysis of CpN and CpG sites can be performed together in a single Pyrosequencing reaction. Each of these positions can be selected individually in the software during the run setup (see figure
Quantification of CpN methylation).
Convenient and improved tools for run analysis
The PyroMark Q24 Advanced analysis software is user-friendly and intuitive, and now provides convenient and improved tools for run analysis. If a problem occurs during the run, or if the system detects an inconsistency with an assay, the software provides specific warning information for each individual well (see figure
Additional warning information). A "Warning Info" button now gives access to additional information about the warning along with recommendations for troubleshooting and preventing its occurrence in subsequent assays (see figure
Troubleshooting recommendations).
Longer Pyrosequencing runs and improved accuracy
PyroMark Q24 Advanced features improved chemistry and instrument operation algorithms that significantly increase the assay read length and accuracy of the base calling functionality, enabling easy analysis of long
de novo sequencing runs. Assay read length was previously limited by background peaks and reduced light signals in the sequencing reaction. The updated chemistry and algorithms of PyroMark Q24 Advanced reduce these background peaks, thereby increasing read length and reliability. Depending on the sequence to be analyzed, highly accurate read lengths of 140 or more bases can be obtained in just a single PyroMark Q24 Advanced reaction (see figure
Long de novo sequencing runs).
Improved methylation analysis at any position
PyroMark Q24 Advanced enables improved methylation quantification in long sequence runs at any sequence position. Previously, analysis of methylation sites further away from the sequencing primer could be uncertain, but now with longer read lengths and higher accuracy, methylation quantification is highly reliable throughout the entire sequencing run (see figure
Analysis of 16 CpG sites in a long sequence run).
Improved sequencing accuracy in homopolymers
Bisulfite conversion in DNA methylation analysis leads to frequent poly T stretches in the nucleotide sequence, and analysis of CpG sites directly after such T homopolymers has previously been challenging due to uncertain quantification of the light signal at these sites. The increased accuracy of PyroMark Q24 Advanced enables reliable quantification of CpG methylation behind and even within a stretch of 8 T nucleotides (see figure
Improved methylation quantification in homopolymers).
Analysis of mutations over long sequences
PyroMark Q24 Advanced also provides reliable quantification of multiple polymorphisms in a single assay. Since single nucleotide polymorphisms (SNPs) and other mutations are often not located close to one another, traditional Pyrosequencing chemistry usually requires separate assays for each mutation site to be analyzed. The new chemistry of PyroMark Q24 Advanced allows much longer runs, enabling reliable analysis of more than one mutation or SNP in the same run (see figure
Quantitative mutation analysis in long sequence runs).