Originally published as Genetics Published Articles Ahead of Print on November 10, 2008.

Genetics, Vol. 181, 341-345, January 2009, Copyright © 2009
doi:10.1534/genetics.108.092460

Extensions of the Coalescent Effective Population Size

Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138

1 Corresponding author: 4100 Biological Laboratories, 16 Divinity Ave., Cambridge, MA 02138.
E-mail: wakeley{at}fas.harvard.edu

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 population size should be lifted. Third, even if the coalescent effective population size does not exist in the mathematical sense, it may be difficult to reject Kingman's coalescent using genetic data.