Electronic Genome Mapping
Extending the Range of Genomic Interrogation
Structural variants (SVs) are the largest source of genetic variation — affecting 3–5x more DNA per genome than single-nucleotide variants (SNVs). As a major contributor to genomic function and disease, detection of this variant type is critical.
Unfortunately, traditional methods have left many SVs undetected, even after decades of innovation. Until now. The introduction of genome mapping finally offers a comprehensive view beyond single nucleotide polymorphisms (SNPs) and small indels, broadening your understanding of SVs and expanding your research in new directions.
Whole Genome SV Detection to Electrify Your Research
Using solid-state nanodetectors to survey long DNA molecules—reads are used to construct high-density maps with long-range information to detect SVs. Optical DNA mapping technologies that rely on the use of expensive optical imaging are limited in the resolution of neighboring tags by the diffraction limit of light.
EGM uses electronic detection to identify tags and does not have the same limitations as optical methods, providing superior resolution of small intervals. This high-density information makes it possible to identify both balanced and unbalanced SVs, as small as 300 bp, in addition to larger chromosomal aberrations and genetic variation missed by next-generation sequencing (NGS).
EGM involves simple, intuitive workflows, eliminating the need for cytogenetics technical expertise, while delivering on the promise of easy-to-use, accurate, low-cost, whole-genome SV analysis.
How It Works
The OhmX Genome Prep workflow combines DNA isolation with DNA tagging into a streamlined process that prepares high molecular weight DNA for electronic genome mapping. Using sequence-specific nicking enzymes, the DNA is labeled at recognition sites, then tagged with a proprietary marker to enable high-density, whole-genome mapping. The tagged DNA is coated with a DNA-binding protein to enhance electronic signal detection.
Central to our EGM technology are novel, solid-state nanodetectors that house 256 parallel nanochannels, each with its own pair of electronic sensors.
Enhanced SV Mapping for Long DNA Molecules
When an object occupies a significant space in a current path, it creates an electronic current blockade, which is measurable as a change in the voltage drop across a nanochannel. Coated DNA in a nanochannel reduces current flow, with larger coated and tagged DNA, causing a greater blockade. Measuring these current blockades provides information about the stretches of DNA that are tagged and untagged.
Each dual sensor in all 256 nanochannels detects changes in the voltage drop as a function of time as molecules pass through the detector. Transit times for these segments are converted to physical distances using advanced signal processing algorithms.
The unique spacing between tags can be aligned and mapped to reference sequences, allowing identification of structural variants in the sample compared to reference sequences. If a tag in the sample is shifted relative to the expected tag position in the reference genome, it is indicative of a structural variant. Measuring the difference in tag positions within the sample relative to the reference genome is how EGM can detect genome-wide structural variation.
Learn More About the Power of EGM
Download the electronic genome mapping white paper to discover how the Ohmx Platform enables high resolution, structural variant detection genome-wide.
Explore the EGM Pipeline
