Genetic drift

Genetic drift is a mechanism of evolution that contributes to the variation in the genetic makeup of a population. It is the change in the frequency of an existing gene variant (allele) in a population due to random sampling of organisms.

Overview

Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies. Genetic drift can result in genetic traits being lost from a population or becoming widespread in a population without respect to the survival or reproductive value of the alleles involved.

Causes

A population's allele frequency is influenced by many factors, including migration, mutation and selection. However, genetic drift is defined as changes in allele frequency that cannot be ascribed to genetic mutation or migration.

Effects

The effects of genetic drift are numerous and can be significant. Genetic drift can lead to a loss of genetic diversity within populations, which can affect the population's ability to adapt to new environmental challenges. It can also lead to the fixation of harmful alleles and the loss of beneficial alleles.

See also

• Population genetics
• Genetic variation
• Natural selection
• Mutation
• Migration (biology)

Genetic_drift

• 
  Random sampling genetic drift
• 
  Random genetic drift chart
• 
  Population bottleneck
• 
  Founder effect with drift