Abstract
We use population genetics theory and computer simulations to demonstrate that population bottlenecks cause a characteristic mode-shift distortion in the distribution of allele frequencies at selectively neutral loci. Bottlenecks cause alleles at low frequency (<0.1) to become less abundant than alleles in one or more intermediate allele frequency class (e.g., 0.1-0.2). This distortion is transient and likely to be detectable for only a few dozen generations. Consequently only recent bottlenecks are likely to be detected by tests for distortions in distributions of allele frequencies. We illustrate and evaluate a qualitative graphical method for detecting a bottleneck-induced distortion of allele frequency distributions. The simple novel method requires no information on historical population sizes or levels of genetic variation; it requires only samples of 50 20 polymorphic loci and approximately 30 individuals. The graphical method often differentiates between empirical datasets from bottlenecked and nonbottlenecked natural populations. Computer simulations show that the graphical method is likely (P > .80) to detect an allele frequency distortion after a bottleneck of ≤20 breeding individuals when 8 to 10 polymorphic microsatellite loci are analyzed.
| Original language | English |
|---|---|
| Pages (from-to) | 238-247 |
| Number of pages | 10 |
| Journal | Journal of Heredity |
| Volume | 89 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 1998 |
Funding
From the Division of Biological Sciences, University of Montana, Missoula, MT 59812 (Luikart and Allendorf), the Laboratoire de Modelisation et de Biologie Evolutive, I.N.R.A./U.R.L.B., Montpellier, France (Cornuet), and the School of Biological Science, University of New South Wales, Sydney, Australia (Sherwin). G. Luikart is currently at the Laboratoire de Biologie des Populations d’Altitude, CNRS, Université Joseph Fourier, BP 53 F-38041, Genoble Cedex 9, France. We thank S. Forbes, D. Tallmon, and A. Taylor for comments on earlier versions of this manuscript. P. England provided helpful discussions and comments. Funding for analyses of mountain sheep samples was provided by the Boone and Crocked Club and the National Rifle Association. J. Hogg and S. Forbes kindly provided unpublished data. Mountain sheep tissue samples were provided by J. McCarthy, J. Cross, and J. Firebaugh (Montana Department of Fish Wildlife and Parks), O. Dyre, H. Langin, A. Peat, A. Wolterson, and B. Lincoln (British Columbia Ministry of Environment, Wildlife Branch), Jon Jorgenson (Alberta Fish and Wildlife Service), M. Miller (Colorado Department of Fish and Wildlife), J. Hogg, and Marco Festa-Bianchet. Address correspondence to Gordon Luikart at the address above or e-mail: [email protected].