Jun 29, 2021

Sequencing 101: Whole Genome Sequencing for Rare Diseases

Posted by in categories: biotech/medical, genetics

Big fan of long-read sequencing. It helped diagnose my rare disease when conventional sequencing failed.

What’s the Difference between Short-Read Sequencing and Long-Read Sequencing? Like their names suggest, short-read sequencing looks at DNA in short snippets (100−350 base pairs) while long-read sequencing measures long fragments of DNA (tens of thousands of base pairs). Why does that matter? Well, when trying to characterize a human genome that has two copies (one maternal and one paternal), each 3.2 billion base pairs in length — having longer snippets of DNA means you: Need fewer snippets to make up the length of the whole genome and have no gaps where the sequence is unknown Can more easily map how one region of the genome is connected to another region Have the ability to phase or determine which copy of a gene, maternal or paternal, a mutation occurs in.

PacBio long-read sequencing provides the most comprehensive view of genomes, transcriptomes, and epigenomes.


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  1. Good post John!