Microevolution

Microevolution refers to changes in gene frequency in a population from one generation to the next and to the processes that cause those changes. These processes include mutation, non-random mating, gene flow, genetic drift, and natural selection.

Definition

Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow, and genetic drift.

Processes

Mutation

Mutation is a change in a DNA sequence, usually occurring because of errors in replication or repair. Mutation can introduce new genetic variation into the gene pool of a population.

Selection

Selection is the process by which certain phenotypes are favored to survive and reproduce over others. Selection can be divided into three types:

• Natural selection: It favors the survival of organisms that are best adapted to their environment.
• Artificial selection: It involves humans selecting for desirable traits in organisms.
• Sexual selection: It involves organisms selecting mates based on certain traits.

Gene Flow

Gene flow is the transfer of genetic variation from one population to another. If the rate of gene flow is high enough, then two populations are considered to have equivalent allele frequencies and therefore effectively be a single population.

Genetic Drift

Genetic drift is the change in allele frequency from one generation to the next that occurs due to chance. This is particularly important in small populations where chance events can have a larger impact on the gene pool.

See Also

• Macroevolution
• Evolution
• Population genetics

References

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Microevolution

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  Gene duplication

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  Mutation and selection diagram

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  Random genetic drift chart