Genetic stability and genetic drift describe how genetic traits are maintained or altered across successive generations. In cannabis genetics, these concepts are particularly important due to the species’ long history of informal selection, geographic movement, and extensive hybridisation.
This page examines how and why cannabis genetics change over time, explaining the mechanisms behind stability, variation, and divergence. Understanding these processes is essential for interpreting lineage claims, classification models, and historical genetic documentation.
This discussion forms part of the Genetic Classification section of the Cannabis Genetics Archive and should be read within the framework established by the Archive Methodology.
What Is Genetic Stability?
Genetic stability refers to the degree to which inherited traits remain consistent across generations within a population or lineage. In theory, a genetically stable population exhibits relatively predictable inheritance of core characteristics.
In practice, complete stability is rare. Even under controlled conditions, genetic recombination introduces variation. Over time, this variation can accumulate, leading to gradual divergence from earlier genetic states.
Stability should therefore be understood as a relative condition rather than an absolute one.
What Is Genetic Drift?
Genetic drift describes random changes in gene frequency that occur from one generation to the next. Unlike selection, drift does not operate according to adaptive advantage. Instead, it reflects chance inheritance events, particularly within small or isolated populations.
In cannabis genetics, drift has played a significant role due to factors such as:
- Small population sizes during early cultivation
- Geographic isolation of landrace populations
- Informal selection practices
- Limited genetic pools during early hybridisation
Over time, drift can result in noticeable genetic divergence even without intentional selection.
Stability, Drift, and Classification
Understanding stability and drift is essential when interpreting genetic classification. Classification models often assume a degree of consistency that may not exist across generations.
Populations labelled using the same classification terms may differ genetically due to drift, environmental influence, or repeated recombination. This helps explain why visual similarity does not guarantee genetic continuity.
These limitations are discussed further within Indica, Sativa & Hybrid Explained and Cannabis Classification Models.
Impact of Hybridisation on Stability
Hybridisation accelerates genetic change by combining genetic material from distinct populations. While hybridisation increases diversity, it also reduces predictability across generations.
In highly hybridised species such as cannabis, repeated crossing can rapidly reshape genetic composition, making long-term stability difficult to maintain without deliberate isolation.
This process contributes to the polyhybrid nature of many modern genetic populations.
Genetic Drift in Landrace Populations
Landrace populations offer valuable insight into genetic drift. Isolated by geography and shaped by local conditions, these populations experienced drift over long timeframes.
While landraces are often perceived as genetically uniform, they frequently contain internal diversity shaped by drift and environmental pressure.
Further exploration of geographic population development can be found within the Landrace Origins section.
Interpreting Stability Claims
Claims of genetic stability should be interpreted cautiously. Without rigorous population control and documentation, stability is relative rather than absolute.
The Genetics Archive presents stability as a conceptual framework for understanding inheritance trends, not as a guarantee of fixed genetic identity.
This perspective supports critical evaluation of lineage narratives and historical classification systems.
How the Genetics Archive Applies These Concepts
Within the Cannabis Genetics Archive, genetic stability and drift are used to contextualise historical documentation rather than to validate or invalidate specific genetic claims.
By acknowledging both stability and change, the archive provides a more accurate and responsible account of genetic history.
Readers seeking broader context may also explore Phenotypes vs Genotypes and Lineages & Heritage to understand how inheritance and variation interact across populations.
This page completes the Genetic Classification section by addressing how genetics persist, adapt, and diverge over time.
