Technology

The Process – Molecular Combing

Molecular Combing is a user-friendly technology for the direct visualization and analysis of single DNA molecules. DNA is stretched and attached to a specially-treated glass surface. Subsequent labelling with fluorescent probes and automated scanning provides a visual read-out of the DNA.

Molecular Combing provides clear visualization of genomic anomalies and large scale DNA modifications. Large scale DNA rearrangements have a significant impact on human health and are directly involved in predisposition onset and prognosis for cancer as well as a plethora of genetic disorders. There are few technologies capable of direct detection and characterization of these genomic anomalies, as such, Molecular Combing in bridging the gap between examining large chromosomal abnormalities and small sequence changes.

The Molecular Combing procedure is automated by our Molecular Combing System (MCS) and has a resolution ranging from a few kilobases to a megabase. This has a plethora of applications in DNA structural and functional analysis with broad applications in the fields of molecular diagnostics, oncogenetic testing, pharmacogenomics and medical research.

the molecular combing process

Genomic Morse Code (GMC)

With Molecular Combing, around 100 genomes are spread with a uniform stretching factor on a coverslip as megabase-long-linear and parallel fibers. Multiple genetics markers can be detected using fluorescentlabeled DNA probes.

The direct measurement of the probe and gap lengths are possible as a result of a constant stretching factor (2 kb = 1 μm).

Depending on a proprietary probe design strategy, “Genomic Morse Code”, multiple types of rearrangements can be detected: amplifications, deletions, repeats, inversions and translocations.

Genomic Morse Code (GMC) is a probe-designing strategy which overcomes the current limitation of identifying parts of a locus of interest and its arrangements. Indeed, with only a few distinguishable probe types, GMC allows the coverage of large loci. The strategy underlying GMC is to the use spatial distribution of the probes to provide more information than the probes by themselves: a specific spacing between probes, or a specific pattern of successive probes, can provide means to distinguish numerous regions on the locus. The implementation of GMC is the added value of Genomic Vision.

Using the GMC approach, it is possible to cover several megabases – potentially one whole chromosome – in replication studies, or to study rearrangements in a region tens of megabases long – potentially on a whole-genome scale. This will allow, for example, for the detection of a large set of possible rearrangements, previously reported or not, in a single analysis.

See an animation of the Molecular Combing process

Genomic Vision