Massively parallel sequencing: gene panels, exome and genome
How short-read massively parallel sequencing works, what read depth and allele fraction mean, and how to choose between a gene panel, exome and genome, including what each one misses and how secondary findings are handled.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Massively parallel (next-generation) sequencing reads millions of short DNA fragments at once, then aligns them to the reference genome.
- The same chemistry is used three ways. A panel looks at a set of genes chosen for a phenotype, an exome at all coding exons, and a genome at everything.
- Two numbers matter on every report: read depth (how many reads cover a base) and variant allele fraction (the share of reads carrying the variant).
Loading the rest of the note…
Finished reading?
Sources
- Thompson & Thompson Genetics and Genomics in Medicine (9th ed.)Elsevier (Cohn, Scherer and Hamosh, eds), 2023
- ACMG SF v3.3 list for reporting of secondary findings in clinical exome and genome sequencing: a policy statement of the American College of Medical Genetics and GenomicsGenetics in Medicine (2025;27(8):101454), 2025
- One in seven pathogenic variants can be challenging to detect by NGSGenetics in Medicine (Lincoln et al., 2021;23:1673-80), 2021
- Australian Genomics resources for cliniciansAU/NZAustralian Genomics
- Treasury Laws Amendment (Genetic Testing Protections in Life Insurance and Other Measures) Act 2026AU/NZAustralian Government, 2026
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback