By Alicia Prince Updated Aug 30, 2022
While mutation and genetic drift both influence the genetic makeup of future generations, they stem from distinct mechanisms. Both phenomena can affect any species, regardless of its size or habitat. Although the triggers for mutation and genetic drift differ, certain mutagenic causes can be mitigated.
A mutation is a lasting alteration in the DNA sequence of a gene. This change can modify the gene’s message, potentially shifting the amino‑acid sequence of the resulting protein. Consequently, all descendant cells inherit the new trait encoded by that gene.
Mutations arise under various conditions. High‑energy radiation from sources such as radioactive materials or X‑rays can damage DNA directly. Sunlight’s ultraviolet rays create abnormal base pair links that propagate to daughter cells. Additionally, spontaneous mutations occur when nucleotides shift into alternative chemical forms, altering hydrogen‑bond patterns and leading to random base substitutions.
Genetic drift describes random fluctuations in a population’s allele frequencies over generations. Events like natural disasters or atypical weather can leave survivors whose genetic makeup is more a matter of chance than fitness. Unlike mutation, drift does not target specific genes; it reflects stochastic shifts that shape the overall genetic composition.
All populations experience genetic drift, but the impact is stronger in small groups. Drift can erode genetic diversity, diminishing a species’ adaptive potential. While natural selection thrives on variation, it cannot generate new genetic variance; that supply must come from mutation.
