Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-19T06:31:37.547Z Has data issue: false hasContentIssue false

A correction to the exact test based on the Ewens sampling distribution

Published online by Cambridge University Press:  14 April 2009

Montgomery Slatkin
Affiliation:
Department of Integrative Biology, University of California, Berkeley, CA 94720-3140, USA
Rights & Permissions [Opens in a new window]

Summary

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The exact test for neutrality based on the Ewens sampling distribution described previously (Slatkin, 1994) is not correct. The problem is that the test as described is based on the probability of the ordered configuration of numbers of alleles, while it should be based on the probability of the unordered configuration. The correctly implemented exact test leads to results that are similar to those from the homozygosity test proposed by Watterson (1977) for relatively small sample sizes but can still differ substantially for larger sample sizes. Programs to perform the exact test are available from the author.

Type
Short Paper
Copyright
Copyright © Cambridge University Press 1996

References

Ewens, W. J., (1972). The sampling theory of selectively neutral alleles. Theoretical Population Biology 3, 87112.CrossRefGoogle ScholarPubMed
Ewens, W. J., (1979). Mathematical Population Genetics. Berlin: Springer.Google Scholar
Keith, T. P., Brooks, L. D., Lewontin, R. C., Martinez-Cruzado, J. C., & Rigby, D. L., (1985). Nearly identical distributions of xanthine dehydrogenase in two populations of Drosophila pseudoobscura. Molecular Biology and Evolution 2, 206216.Google ScholarPubMed
Slatkin, M., (1994). An exact test for neutrality based on the Ewens sampling distribution. Genetical Research 64, 7174.CrossRefGoogle ScholarPubMed
Stewart, F. M., (1977). Computer algorithm for obtaining a random set of allele frequencies for a locus in an equilibrium population. Genetics 86, 482483.Google Scholar
Watterson, G. A., (1977). Heterosis or neutrality? Genetics 85, 789814.CrossRefGoogle ScholarPubMed