May 23, 2024
Optical Genome Mapping

Global Optical Genome Mapping: enabling Novel Insights into Genomic Structure And Disease

Optical genome mapping is a technique that uses optical microscopy to establish the spatial arrangement of large DNA molecules that have been labelled with fluorescent markers. This allows researchers to generate high-resolution whole-genome maps that reveal structural variations in an individual’s genome at megabase-scale resolution. Optical maps provide information about genome architecture that is not accessible through short-read sequencing alone.

History and Development of Optical Mapping Technology

The foundations for Optical Genome Mapping were laid in the late 1980s and early 1990s with the development of techniques for isolating and stretching single DNA molecules. In the late 1990s, researchers at OpGen began developing automated instrumentation and software for generating whole-genome maps of bacteria. Over the following decade, they applied optical mapping to numerous microbial genome projects and human disease research. Advancements in DNA labeling, microscopy, and genome assembly algorithms have increased map contiguity and resolution. Today, several companies offer commercial optical mapping platforms to support clinical and research applications.

Applications in Microbial Genomics and Public Health

Optical mapping has proven highly valuable for finishing bacterial genome assemblies and elucidating structural variants associated with antimicrobial resistance or virulence. By characterizing large structural variations, optical maps have helped public health agencies monitor the emergence and spread of pathogenic bacterial strains. Optical mapping was instrumental in assembling the genome of the Ebola virus and elucidating virulence factors of organisms like Listeria monocytogenes. It continues to support outbreak investigations and phylogenomic analyses of infectious diseases worldwide.

Revealing Genomic Rearrangements in Cancer

One of the most significant early applications of optical mapping was its use in characterizing complex chromosomal rearrangements involved in cancer. Optical maps provided first glimpses of the scope and complexity of structural changes in cancer genomes, including translocations, deletions, amplifications, and inversions missed by other methods. Since then, optical mapping has aided research on genetic drivers and progression pathways in numerous cancers. It has proven particularly useful for analyzing rare and complex genomic changes involved in pediatric cancers and treatment-resistant disease.

Understanding Genomic Disorders

Some of the earliest clinical applications of optical mapping involved deciphering the complex rearrangements underlying genomic disorders. These include diseases caused by duplications or deletions of large genomic regions, such as Williams-Beuren syndrome, Smith-Magenis syndrome, and Potocki-Lupski syndrome. Optical maps have revealed pathogenic genomic architectures in these and other disorders, providing insights into genotype-phenotype correlations. Today, optical mapping supports diagnostics for chromosomal anomalies like deletions or translocations that underlie developmental disorders.

Role in Structural Variation Discovery Projects

Large-scale projects like the Human Genome Structural Variation Consortium and Genome in a Bottle Consortium have relied on optical mapping to validate and refine structural variants identified through other methods. Since most structural variants are far too complex to resolve using short-read sequencing alone, optical mapping plays an important role in finishing variant discovery. It has been indispensable for characterizing complex genome architectures and variant haplotypes in the human reference genomes being established by these collaborations.

Resolving Genomic Structures in Model Organisms

Optical mapping has also transformed genome projects in numerous agriculturally or medically important non-human species. It has been used to improved genome assemblies and variant discovery in model organisms like mouse, zebrafish, fruit fly, nematode, and rice. In species where chromosomes are difficult to manipulate through cloning or cytogenetics, optical mapping provides a higher-resolution alternative. As map resolution and contiguity improve, single-molecule maps are revolutionizing understanding of structural variation and evolution in diverse species.

Clinical Applications in Genetic Disease Diagnostics

As optical mapping platforms achieve the scale, throughput, and accuracy needed for clinical diagnostics, they are increasingly being adopted in genetics labs worldwide. Genome-wide optical maps can rapidly scan a patient’s genome to detect large chromosomal aberrations that may underlie a genetic condition. By supplementing microarray and sequencing analyses, optical mapping is helping elucidate more genetic disease cases. It shows particular promise for prenatal screening, where analyzing fetal structural variations could improve diagnosis of conditions like Down syndrome. Combined with other methods, optical mapping enables robust clinical cytogenomic analysis.

Over three decades, optical mapping technology has advanced enormously, finding diverse applications ranging from pathogen genomics to human disease research. It has carved out a unique niche by revealing genome-scale structural variations inaccessible through sequencing alone. As map resolution and throughput increase further, optical mapping promises to continue transforming research into microbial evolution and pathogenesis, cancer genomics, human genetic disorders, and clinical cytogenomics. By illuminating complex genomic architectures, it will continue providing novel biological insights for many years to come

1. Source: Coherent Market Insights, Public sources, Desk research.
2. We have leveraged AI tools to mine information and compile it.