genetic drift
Population allele fluctuation
Genetic drift is the random change in how common a gene variant is within a population over generations.
Unlike natural selection, drift has nothing to do with which traits help survival—it's pure chance, like a coin flip repeated across time.
Small populations are especially vulnerable: The cheetah's lack of genetic diversity likely resulted from genetic drift during a population bottleneck.
The effect can cause traits to disappear entirely or become universal without any adaptive advantage.
Few people in an area
- bottleneckConstriction limiting throughput
- inbreedingReproduction between close relatives
- colonizationForeign territorial takeover
- demographicStatistical population category
Selecting by pure chance
- stochasticRandomly determined, statistically describable
- chance eventsUnintended happenings, not designed
- sampling errorSubset-population value difference
- fixationPersistent mental attachment
Small hereditary changes within populations
- speciationFormation of distinct species
- adaptationFitting to new conditions
- natural selectionDifferential reproductive success
- mutationPermanent DNA alteration
small population
Few people in an area
- bottleneckConstriction limiting throughput
- inbreedingReproduction between close relatives
- colonizationForeign territorial takeover
island population · demographic · population crash · endangered species
random sampling
Selecting by pure chance
- stochasticRandomly determined, statistically describable
- chance eventsUnintended happenings, not designed
- sampling errorSubset-population value difference
microevolution
Small hereditary changes within populations
- speciationFormation of distinct species
- adaptationFitting to new conditions
- natural selectionDifferential reproductive success
mutation · genotype · allele · phylogenetics · coalescence
genetic driftnatural selection
Differential reproductive success
selective pressure · survival of the fittest · sexual selection · competitive advantage · convergent evolution
drift, genes, genetic, gene, genetics, genome, genetically, genomic, genomes