You've probably already done an ancestry test. Millions of people have. You sent a tube of saliva to a lab, waited a few weeks, and got back a pie chart of continental ancestry percentages and some distant cousin matches.
What you may not have realised is that the DNA data behind that test is a very small, specific slice of your genome — optimised for genealogy, not health. And the difference between what ancestry tests sequence and what whole genome sequencing (WGS) captures is significant enough that it changes what you can meaningfully learn.
What ancestry tests actually genotype
Services like 23andMe, AncestryDNA, and MyHeritage use a technology called SNP array genotyping. Rather than reading your entire genome, they scan for a specific set of single nucleotide polymorphisms (SNPs) — individual positions in the DNA where the base pair commonly varies between people.
A typical SNP array covers around 600,000 to 700,000 SNPs. Sounds like a lot. But the human genome contains approximately 3.2 billion base pairs. The array is sampling less than 0.02% of your genome.
Those SNPs are chosen because they're: - Common in the population (useful for ancestry inference through statistical patterns) - Informative for genealogical matching - Associated with a small number of well-replicated traits and health associations
The health reports that ancestry companies offer — BRCA1/BRCA2 status, certain pharmacogenomic variants, carrier status for a few conditions — are derived from this same array. They look for specific SNPs known to be associated with those conditions. But they only check the variants they're looking for. Unknown variants, rare variants, and entire classes of genetic variation are invisible.
What whole genome sequencing actually reads
Whole genome sequencing reads every base pair in your genome, typically at 30x coverage — meaning each position is read an average of 30 times to reduce sequencing errors. The output is a raw file (usually in FASTQ format, later processed into a VCF) containing your complete genomic sequence.
30x WGS detects: - All common SNPs (the same ones ancestry tests check, plus millions more) - Rare variants — the ones present in less than 1% of the population - Copy number variants (CNVs) — regions where you have more or fewer copies of a gene than typical - Structural variants — larger rearrangements of genetic material - Insertions and deletions across the genome
This matters for health because many clinically significant genetic variants are rare. They don't show up on ancestry arrays because they're not common enough to be included. BRCA1 has hundreds of pathogenic variants; a SNP array might check for the three most common ones (the ones prevalent in Ashkenazi Jewish populations) but miss dozens of others.
The BRCA example
23andMe's BRCA1/BRCA2 test looks for three specific variants. If your ancestry test returns "no variants detected" for BRCA, that doesn't mean you don't carry a BRCA mutation — it means you don't carry those three specific ones. There are over 1,700 known pathogenic or likely pathogenic BRCA variants in ClinVar. The SNP array checks for 0.2% of them.
This is not a hypothetical edge case. Medical genetics has documented cases where women with a family history of breast cancer tested negative on direct-to-consumer ancestry tests, only to receive a positive result from clinical sequencing later. The ancestry test was not wrong — it was answering a narrower question than the person thought they were asking.
Pharmacogenomics: where ancestry data is genuinely useful
One area where ancestry-style genotyping is clinically valuable is pharmacogenomics (PGx) — understanding how genetic variants affect drug metabolism. Most PGx-relevant variants are common SNPs that are well-captured by SNP arrays.
CYP2D6, CYP2C19, CYP2C9, SLCO1B1, DPYD, TPMT — these are genes where specific variants significantly affect how your body processes common medications including antidepressants, statins, codeine, and certain chemotherapy agents. The CPIC guidelines (Clinical Pharmacogenomics Implementation Consortium) translate these variants into specific prescribing recommendations.
Your ancestry DNA file contains much of this information. Many people don't know this because ancestry companies don't surface it — but you can upload your raw DNA file to tools like Promethease or use the foreverbetter genomic layer to extract PGx context from existing ancestry data.
Where WGS adds value
Whole genome sequencing adds the most value in several situations:
Rare disease investigation — if you or a family member has an undiagnosed condition, WGS is the appropriate starting point because SNP arrays will miss rare causal variants.
Complete BRCA and cancer gene assessment — if you have a family history of hereditary cancer syndromes (breast, ovarian, colorectal, pancreatic), WGS or at minimum targeted panel sequencing is necessary for a meaningful assessment.
Deep longevity context — for people who want the most complete picture of their genetic risk factors, WGS provides data that array-based tests cannot. This includes: - Comprehensive APOE status (Alzheimer's and cardiovascular risk) - Full assessment of rare cardiovascular risk variants - Aging hallmark gene assessment (SIRT family, FOXO3, CETP, APOB) - Comprehensive carrier screening
Polygenic risk scores — while most PRS are developed on common SNPs and work fine from ancestry data, newer, more accurate PRS models use rare variant data that only WGS provides.
The cost question
In 2007, sequencing a human genome cost approximately $10 million. By 2023, clinical-grade 30x WGS was available for $300–400. Consumer WGS (lower depth, less clinical-grade QC) is available for under $100 from some providers.
Ancestry tests typically cost $60–$100. For the purposes of health and longevity analysis, the gap between ancestry genotyping and full WGS has narrowed considerably.
What this means for foreverbetter members
foreverbetter is built around biomarkers as the core annual loop. Genetics is optional, additional context.
If you already have an ancestry test file (23andMe, AncestryDNA, MyHeritage, or similar), you can upload it to foreverbetter at no extra cost. We'll extract the health-relevant information — pharmacogenomics, known risk variants, longevity-associated SNPs — within the confidence limits of what that data actually captures.
If you have a 30x WGS file (from Nebula Genomics, Dante Labs, Sequencing.com, or a clinical provider), you can upload that instead. The additional depth means broader coverage of rare variants, more complete BRCA and cancer gene assessment, and richer aging hallmark analysis.
In both cases, the genetic layer is added on top of your biomarker results — not treated as equivalent to them. DNA tells you tendencies. Blood tells you what's actually happening right now.