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 uniformly and irreversibly attached to a specially-treated glass surface. This technology improves the structural and functional study of DNA modifications and makes it possible to explore the whole genome at a high resolution in a single analysis.

Molecular Combing provides clear visualization of genomic anomalies and large scale DNA modifications that have implications in cancer genomics and genetics diseases.

Large scale DNA rearrangements are proving to be significant in human polymorphisms, cancer or genetic diseases and very few methods can detect them accurately. By precisely screening the genome in a single and global overview, Molecular Combing bridges the gap between examining large chromosomal abnormalities and small sequence-specific changes, e.g., SNPs.

The Molecular Combing procedure is automated by our Molecular Combing System (MCS).

This method, with a high resolution ranging from a few kilobases to megabases, has many applications in the field of molecular diagnostics, allowing structural and functional analysis.

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.