Each DNA is originally a single molecule, where lies the truest information of life. Direct Genomics' unique single molecule fluorescence sequencing technology can directly see, sequence and decode individual DNA molecules. No PCR, no bias.
Direct Genomics’ Single Molecule Direct Sequencing technology utilizes wide-field total internal reflection fluorescence (TIRF) microscopy for the parallel detection of multiple fluorescently labeled single molecules. Exquisitely designed TIRF illumination excites molecules only within a thin layer above the flow cell surface, rejecting undesirable background noise from the sample medium, yielding excellent signal-to-noise ratio for single molecule detection.
Direct Genomics' patented “virtual terminators” empower sequencing with superior fidelity and speed. With the cleavable terminator and fluorescence label tethered at the same site, the nucleotide analog performs in similar manner as the natural nucleotide during DNA synthesis. During each incorporation cycle, only one of such nucleotide analog can be added to each strand due to the blocking effect of the tethered terminator. The flow cell is imaged at this stage, after which the terminator and fluorescence label are cleaved. The sample is then ready for the sequencing of the next cycle.
DirectCall, the particular basecalling algorithm tailored for single molecule fluorescence sequencing, provides a powerful tool to precisely detect, locate, register and identify signal from each individual nucleotide. While avoiding phasing/prephasing and GC bias issues that are intrinsic in traditional NGS platforms, DirectCall also achieves the highest ever accuracy amongst existing single molecule sequencing technologies.