Effective Population Size: Biological Duality, Field & Molecular Approaches

Effective population size

What is it? An aid to calculation in population genetics, introduced by Sewall Wright. The rate of change of the genetic make-up of a population by genetic drift — fluctuations in allele frequencies caused by random sampling — is inversely related to the effective population size, Ne. Ne is measured with reference to an ideal ‘Wright–Fisher’ population. This has a fixed number of N diploid bree...

Electric - Magnetic Duality and Effective Field

The effective size of a subdivided population.

This paper derives the long-term effective size, Ne, for a general model of population subdivision, allowing for differential deme fitness, variable emigration and immigration rates, extinction, colonization, and correlations across generations in these processes. We show that various long-term measures of Ne are equivalent. The effective size of a metapopulation can be expressed in a variety o...

Testing demographic models of effective population size.

Due to practical difficulties in obtaining direct genetic estimates of effective sizes, conservation biologists have to rely on so-called 'demographic models' which combine life-history and mating-system parameters with F-statistics in order to produce indirect estimates of effective sizes. However, for the same practical reasons that prevent direct genetic estimates, the accuracy of demographi...

Extensions of the coalescent effective population size.

We suggest two extensions of the coalescent effective population size of Sjödin et al. (2005) and make a third, practical point. First, to bolster its relevance to data and allow comparisons between models, the coalescent effective size should be recast as a kind of mutation effective size. Second, the requirement that the coalescent effective population size must depend linearly on the actual ...