Genotyping identifies the genetic variants present at positions of interest. Understanding what was measured is the first step toward understanding what a result can support.
A genotype refers to the genetic makeup at a particular location or set of locations. Genotyping is the process of determining that information. Different techniques can be used, and the scope may be a single position, a defined panel, or a larger collection of selected markers.
A common discussion of consumer testing compares marker-based genotyping with sequencing. That comparison is useful, but the terminology has nuance: sequencing data can also be used to determine genotypes. Ask what technology and analysis the provider means rather than relying on the word alone.
A single nucleotide polymorphism, or SNP, involves variation at one DNA base position. SNP markers can be useful in research and some testing applications. They represent one kind of genetic variation; they do not capture every possible difference in DNA.
Seeing a familiar marker name on a report can make the information feel precise. Precision in naming, however, does not establish the importance of that marker for a particular question. Identification and interpretation remain separate tasks.
Some analyses estimate unmeasured information using measured markers and reference data. Such estimates depend on the model and the available comparison data. They should not be silently treated as the same thing as direct laboratory measurement.
When reading a report or raw-data description, look for an explanation of which information is directly observed and which is inferred. If the service does not say, that is a specific question to take back to the provider.
Targeted marker genotyping generally asks about positions selected in advance. Sequencing determines the order of bases across the regions a test is designed to cover. The amount of information, the kinds of findings, and the analysis required can differ considerably.
Neither label guarantees a useful answer for every purpose. A carefully designed targeted assay can fit a narrow question; a broader sequencing approach can create additional interpretive work. Our full comparison of genotyping and sequencing explains how to read these differences without assuming a universal winner.
These details are especially helpful when two services appear to disagree. They may be measuring different things or presenting different interpretations of similar data.
Continue with DNA testing methods and the genome database guide. For a concise official definition, consult the NHGRI glossary entry for genotype.
Genotyping and sequencing can both describe genetic differences, but they collect information in different ways. Learn how selected markers, sequence reads, coverage, and imputation shape the results, and which questions make a method comparison useful rather than confusing.
A DNA kit is the starting point of a service, not a description of everything it can tell you. Compare the question being asked, the laboratory method, the interpretation, and the choices you retain over your sample and data.
Ancestry DNA reports compare inherited patterns with reference groups. Learn why estimates change, why siblings differ, how relative matching differs from regional percentages, and how to combine genetic clues with family records without treating DNA as a definition of identity.
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