SAN FRANCISCO (GenomeWeb) – Boreal Genomics has developed a sequencing technique that it said can improve the detection of low-frequency mutations in cell-free DNA assays, while keeping sequencing costs down.
The firm, which described the technique recently in a paper posted to the BioRxiv preprint server, said that it could be complementary to previous technology it has developed, OnTarget, which targets known activating mutations in cancer genes.
The method, called Proximity Sequencing (Pro-Seq), involves linking both strands of a double-stranded DNA fragment together so that they populate one cluster on an Illumina flow cell. That increases the chances that sequencing errors are compensated for by comparing the two strands of the DNA molecule.
In the study, the Boreal team described both a targeted and a whole-genome approach, using DNA from a cell line and cell-free DNA. They found that on average, they could detect mutations down to a .003 percent frequency and that per-base specificity was 99.9997 percent.
Andre Marziali, Boreal’s chief scientific officer, said that the goal was to develop a technique that would be as good as its OnTarget assay at identifying low-frequency mutations, but would also be able to be broader. The premise behind the OnTarget technology