Genetic Drift

Genetic drift describes random changes in allele frequencies within cannabis populations over successive generations, particularly in small breeding cohorts or isolated seed lines. Unlike directed selection, drift occurs through chance alone—certain traits become more or less common without breeder intervention. This phenomenon is especially relevant when working with limited parent plants, landrace stabilization, or unintentional seed pool bottlenecks. Breeders monitoring phenotypic consistency across generations often document drift as an explanatory factor when unexpected trait variation emerges. Understanding drift helps explain why some cultivar families show increasing heterogeneity despite stable cultivation practices, and why preservation of diverse parent material strengthens long-term breeding projects.

Breeders working with small populations or preserving rare genotypes must account for drift's cumulative effects on trait stability. Maintaining larger parent pools and detailed phenotypic records helps distinguish intentional selection pressure from random genetic fluctuation.