Effective population size

The number of breeding individuals in an idealised population that would show the same amount of dispersion of allele frequencies under random genetic drift or the same amount of inbreeding as the population under consideration. More generally, an effective population size may be defined as the number of individuals in an idealised population that has a value of any given population genetic quantity that is equal to the value of that quantity in the population of interest.

Further reading

• http://www.nature.com/scitable/topicpage/genetic-drift-and-effective-population-size-772523
• http://www.nature.com/scitable/topicpage/genetic-drift-bottleneck-effect-and-the-case-1118