Concepedia

How large must populations be to retain evolutionary potential?

Animal Conservation · 1998 · 431 citations · 12 references

TL;DR

Conservation biology seeks to preserve genetic variation for future evolution, yet estimates of the effective population size needed to maintain this variation range from 500 to 5000, with the upper bound based on the assumption that 90 % of mutations are deleterious. The authors review the arguments supporting an effective population size of 5000 and argue that these rely on unrealistically low mutation rates and high heritabilities. They conduct a literature review of the assumptions underlying the 5000 estimate, focusing on mutation rates and heritability values. They conclude that an Ne of 500–1000 is appropriate at this time.

Abstract

Abstract Maintaining genetic variation for future evolutionary change is an important issue for conservation biology. However, there is controversy over the effective population size ( N e ) required for endangered species to retain their evolutionary potential, with proposed sizes ranging from 500 to 5000. The highest estimate is based on the assumption that 90% of mutations are deleterious. We review the arguments for an effective size of 5000 and conclude that it assumes effective mutation rates that are too low, and heritabilities that are, in general, very high. We conclude that an N e of 500–1000 is appropriate at this time.