A comprehensive lesson exploring the technical and clinical aspects of Whole Genome Sequencing (WGS), covering the workflow from DNA extraction to variant analysis, and comparing short-read versus long-read technologies.
How does RNA sequencing help determine which variants are actually "meaningful" in a cell?
Summary Reflection
How does precision medicine change the way we treat diseases like cancer or rare developmental delays?
Signal changes depend on the specific nucleotide shape.
SIGNAL STRENGTH (pA) OVER TIME
The Quality Control
Coverage (Depth)
The average number of times each base in the genome is read.
30x Coverage = 30 observations per position.
Q-Score (Probability)
Measures base-calling error probability.
Q = -10 log10(e)
Q20 = 99% accuracy | Q30 = 99.9% accuracy
From RAW to READY
@READ_1
GATTACA...
+
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Sequence Alignment
Mapping fragments to a Reference Genome (e.g., hg38) to find their exact chromosomal position.
Variant ID
SNPs, Indels, & Structural Variants
Role of RNA-Seq
While WGS shows the Blueprint, RNA-Seq shows the Activity. It tells us which variants are actually being expressed in a specific tissue.
The Impact of Genomic Precision
Targeted Therapy
Treating cancer based on the tumor's genetic signature, not just its location.
Rare Disease Insight
Ending the diagnostic odyssey for families with unexplained developmental delays.
"Sequencing is not just reading DNA—it's reading the future of medicine."
SAM: (Laughs) Basically, we want a high Q-score. Q30 means the sequence is 99.9% accurate. And "30x Coverage" means we've read every single spot in your genome 30 different times to be sure of the result.
ALEX: And then we map it? Slide 9 shows the "Bioinformatics Pipeline."
SAM: Exactly. We take those raw reads and align them to a reference genome. It's like having a master picture of a puzzle and fitting your pieces onto it to see where they differ. Those differences are the "variants" that tell us about disease risk.
MINUTE 11-12: CLOSING & FUTURE IMPACT
ALEX: Slide 10—The Impact. We're moving from reading DNA to changing the future of medicine. Final thoughts, Sam?
SAM: We’re entering an era where your treatment is as unique as your DNA. Whether it's targeted cancer therapy or solving rare disease mysteries, sequencing is the foundation. Thanks for having me.
