# Genotyping

> Genotyping is reading a plant's DNA at selected markers to identify it, compare it with other plants, check sex or chemotype, or estimate its ancestry.

- Canonical: https://genetixbay.com/knowledge/glossary/genotyping.html
- Also written: DNA test, DNA testing, genetic testing, DNA fingerprinting, genetic fingerprint, genotype test
- Glossary category: Genetics and breeding · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Genotyping is determining which [alleles](https://genetixbay.com/knowledge/glossary/allele.md) a plant carries at a set of DNA markers, usually [SNPs](https://genetixbay.com/knowledge/glossary/snp.md) or short repeats, from a small tissue sample. The result is a genetic fingerprint that can be compared between plants.

## In practice

What genotyping can show:
- whether two cuts are the same [genotype](https://genetixbay.com/knowledge/glossary/genotype.md) (identity) or close relatives;
- likely parentage, if the candidate parents were also tested;
- [seedling](https://genetixbay.com/knowledge/glossary/seedling.md) sex and [cannabinoid](https://genetixbay.com/knowledge/glossary/cannabinoid.md) synthase type, with dedicated markers (Toth et al. 2020);
- broad ancestry and population structure (Sawler et al. 2015; Henry et al. 2020).

What it cannot show: a cultivar's name, its exact [THC](https://genetixbay.com/knowledge/glossary/thc.md) percentage, its flavour or its yield. Those depend on many genes plus how it is grown. A DNA report saying "70% indica" reflects the reference panel used, not a species.

Results are only as good as the database. Comparing a cut to a reference only proves something if the reference itself came from a documented source.

## Don't confuse with

- **Potency testing**: chemistry of the dried flower, not DNA.
- **Genome sequencing**: reads almost the whole genome; genotyping reads chosen markers.
- **Strain ID apps**: guesses from [photos](https://genetixbay.com/knowledge/glossary/photoperiod.md) or names, not DNA.

## Related terms

[SNP](https://genetixbay.com/knowledge/glossary/snp.md), [Marker-assisted selection](https://genetixbay.com/knowledge/glossary/marker-assisted-selection.md), [Genotype](https://genetixbay.com/knowledge/glossary/genotype.md), [Clone-only](https://genetixbay.com/knowledge/glossary/clone-only.md), [Chemotype](https://genetixbay.com/knowledge/glossary/chemotype.md)

## Read more

- [Genotyping: what a DNA test can and can't prove](https://genetixbay.com/knowledge/breeding/genotyping-what-tests-prove.md)
- [How to document lineage evidence (GB-ID evidence levels L0-L4)](https://genetixbay.com/knowledge/breeding/documenting-lineage-evidence.md)

## Sources

1. Henry P, Khatodia S, Kapoor K, et al. 2020. A single nucleotide polymorphism assay sheds light on the extent and distribution of genetic diversity, population structure and functional basis of key traits in cultivated north American cannabis. Journal of Cannabis Research 2:26.
2. Toth JA, Stack GM, Cala AR, et al. 2020. Development and validation of genetic markers for sex and cannabinoid chemotype in Cannabis sativa L. GCB Bioenergy 12(3):213-222. https://doi.org/10.1111/gcbb.12667
3. Sawler J, Stout JM, Gardner KM, et al. 2015. The genetic structure of marijuana and hemp. PLoS ONE 10(8):e0133292. https://doi.org/10.1371/journal.pone.0133292