Genotyping

Genotyping is the laboratory process of determining which genetic variants an individual carries — most commonly single nucleotide polymorphisms, or SNPs. It is the technology underpinning most consumer and clinical genetic testing, and understanding roughly how it works makes results much easier to interpret sensibly.

What is a SNP?

DNA is built from four nucleotide bases: adenine (A), thymine (T), guanine (G) and cytosine (C). They pair predictably — A with T, and C with G — forming the rungs of the double helix.

A single nucleotide polymorphism is a variation at one position in that sequence, where one base is substituted for another. SNPs are the most common form of genetic variation; the human genome contains millions of them.

Most SNPs have no effect at all. Some sit in regions that alter how a protein is built or how strongly a gene is expressed — and those are the ones that can influence disease susceptibility, nutrient metabolism or drug response.

An illustration: sickle cell

Sickle cell anaemia is a clear example of how a single base change matters. Haemoglobin, the oxygen-carrying protein in red blood cells, is built from instructions in the HBB gene. A single base substitution changes one amino acid in the resulting protein, making it prone to clumping. Those clumps distort red blood cells into a rigid crescent shape, so they become trapped in small vessels and break down faster than normal.

One base. One amino acid. A lifelong condition. Most SNPs do nothing remotely as dramatic — which is precisely why context matters when interpreting results.

How genotyping works

DNA is first extracted from a saliva or blood sample. Because the quantity recovered is small, it is amplified — copied many times over — using the polymerase chain reaction (PCR).

At Rightangled we use a variant called KASP (Kompetitive Allele Specific PCR). KASP uses fluorescently labelled probes designed to bind only when a specific version of a SNP is present, so the fluorescent signal produced identifies which variant a sample carries. It is a well-established, widely used platform, valued for its accuracy, cost-effectiveness and flexibility across large numbers of samples.

An important distinction: genotyping is not the same as sequencing. Genotyping checks specific, pre-selected positions in the genome. Sequencing reads the entire sequence in a region, or across the whole genome, and can detect variants nobody was looking for. Genotyping is faster and cheaper; sequencing is comprehensive. Most consumer tests, including ours, use genotyping.

What that means for your results

Because genotyping examines a defined set of markers, a result showing no variants of interest means none of the tested markers were found — not that you carry no genetic risk. This is the single most common misunderstanding about consumer genetic testing, and it is worth being clear about.

Equally, carrying a risk-associated variant does not mean you will develop the associated condition. For common conditions, individual variants typically shift risk modestly, and lifestyle usually has a larger effect.

What genotyping is genuinely useful for

Identifying susceptibility to conditions where early action helps
Understanding how you metabolise nutrients such as folate, B12 or caffeine
Indicating likely response to certain medications
Providing context that motivates practical lifestyle changes

Where a specific inherited condition is clinically suspected, NHS genetic services — with diagnostic-grade testing and genetic counselling — remain the appropriate route.

Testing with Rightangled

Rightangled's DNA tests use validated genotyping methods, with results reviewed by our clinical team, which includes GPhC-registered independent prescribers, and medical oversight from our doctor, Dr Abdullah. Our blood tests complement this by measuring what is happening in your body right now.

Verify us with the General Pharmaceutical Council (registration 9011933), see our LegitScript certification, and read reviews on Trustpilot.