How much of my genome does 23andMe read?

Consumer SNP tests like 23andMe and AncestryDNA read about 0.02% of your genome, roughly 600,000 to 700,000 pre-selected markers. Whole genome sequencing reads all 3.2 billion base pairs.

Is whole genome sequencing better than 23andMe?

Neither is wrong; they are built for different purposes. SNP tests are great for ancestry and basic traits. Whole genome sequencing is what you need to understand how your body processes nutrients, stress, caffeine, and toxins in depth.

What is the coverage difference?

SNP genotyping reads each marker about once (1x). Mosaic uses 30x whole-genome sequencing, where each position is read an average of 30 times, the clinical-grade standard used in research and medicine.

Whole Genome Sequencing vs. 23andMe: What's the Difference?

Consumer DNA tests like 23andMe read about 0.02% of your genome, roughly 600,000 pre-selected markers. Whole genome sequencing reads all 3.2 billion base pairs at 30x depth. Both have a place; the difference is a snapshot versus the whole picture.

By Mosaic BiodataFebruary 5, 20261 min read

Whole Genome Sequencing vs. 23andMe: What's the Difference?

Mosaic reads thisReliability of Vitamin D TestingSome people show "normal" blood levels but still have functional vitamin D deficiency at the tissue level. Your receptor and transport variants tell you whether standard testing reflects your status, or just looks like it does.See this insight

Consumer DNA tests like 23andMe and AncestryDNA read about 0.02% of your genome; whole genome sequencing reads 100% of it. Both have their place, but if you want to understand how your body actually works, the difference between a snapshot and the whole picture matters.

You've probably seen the commercials. Spit in a tube, mail it off, find out you're 4% Scandinavian and should avoid cilantro. Fun party trick. But here's what those tests aren't telling you: they're only reading about 0.02% of your genome. Let that sink in.

Consumer tests like 23andMe and AncestryDNA use something called SNP genotyping. They look at around 600,000 to 700,000 specific genetic markers, the "greatest hits" of known variants. It's like reading the chapter titles of a book and calling it done.

Whole genome sequencing (WGS) is a different beast entirely. It reads all 3.2 billion base pairs of your DNA. Every chapter, every paragraph, every word. At 30x coverage, each position is read an average of 30 times to make sure the data is accurate, the clinical-grade standard used in research and medical settings.

So what does that actually mean for you?

SNP tests can tell you about a handful of well-studied genetic variants. If your question is "do I have the gene for wet earwax?" you're covered.

But if you want to understand how your body actually processes nutrients, responds to stress, metabolizes caffeine, or clears toxins? That requires looking at more than the highlight reel. Many of the genetic variations that influence these pathways aren't included in consumer panels because they're either too rare, too recently discovered, or too complex to fit into a simple "you have this gene / you don't" framework.

The short version

SNP Genotyping (23andMe, AncestryDNA, etc.):

Reads ~0.02% of your genome
~600,000–700,000 data points
1x coverage depth
Best for: ancestry, basic traits

Whole Genome Sequencing:

Reads 100% of your genome
~3.2 billion data points
30x coverage depth (clinical-grade)
Best for: deep genetic insights
You own your data (at Mosaic, anyway)

Neither approach is "wrong"; they're just built for different purposes. If you want to know where your ancestors came from, a $99 test will do the job. If you want to understand how your body actually works at the genetic level, you need more data.

That's the difference between a snapshot and the whole picture. For the full side-by-side, see Mosaic vs 23andMe.

Keep exploring: the Insights Library breaks down the 108 insights Mosaic reads from your DNA, and the reports show how they come together.