Abstract
Drift and migration disequilibrium are very common in animal and plant populations. Yet their impact on methods of estimation of demographic parameters was rarely evaluated especially in complex realistic population models. The effect of such disequilibria on the estimation of demographic parameters depends on the population model, the statistics, and the genetic markers used. Here we considered the estimation of the product Dsigma2 from individual microsatellite data, where D is the density of adults and sigma2 the average squared axial parent-offspring distance in a continuous population evolving under isolation by distance. A coalescence-based simulation algorithm was used to study the effect on Dsigma2 estimation of temporal and spatial fluctuations of demographic parameters. Estimation of present-time Dsigma2 values was found to be robust to temporal changes in dispersal, to density reduction, and to spatial expansions with constant density, even for relatively recent changes (i.e., a few tens of generations ago). By contrast, density increase in the recent past gave Dsigma2 estimations biased largely toward past demographic parameters values. The method was also robust to spatial heterogeneity in density and estimated local demographic parameters when the density is homogenous around the sampling area (e.g., on a surface that equals four times the sampling area). Hence, in the limit of the situations studied in this article, and with the exception of the case of density increase, temporal and spatial fluctuations of demographic parameters appear to have a limited influence on the estimation of local and present-time demographic parameters with the method studied.
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Selected References
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- Barton Nick H., Depaulis Frantz, Etheridge Alison M. Neutral evolution in spatially continuous populations. Theor Popul Biol. 2002 Feb;61(1):31–48. doi: 10.1006/tpbi.2001.1557. [DOI] [PubMed] [Google Scholar]
- Dib C., Fauré S., Fizames C., Samson D., Drouot N., Vignal A., Millasseau P., Marc S., Hazan J., Seboun E. A comprehensive genetic map of the human genome based on 5,264 microsatellites. Nature. 1996 Mar 14;380(6570):152–154. doi: 10.1038/380152a0. [DOI] [PubMed] [Google Scholar]
- Ellegren H. Heterogeneous mutation processes in human microsatellite DNA sequences. Nat Genet. 2000 Apr;24(4):400–402. doi: 10.1038/74249. [DOI] [PubMed] [Google Scholar]
- Estoup A., Wilson I. J., Sullivan C., Cornuet J. M., Moritz C. Inferring population history from microsatellite and enzyme data in serially introduced cane toads, Bufo marinus. Genetics. 2001 Dec;159(4):1671–1687. doi: 10.1093/genetics/159.4.1671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leblois Raphaël, Estoup Arnaud, Rousset François. Influence of mutational and sampling factors on the estimation of demographic parameters in a "continuous" population under isolation by distance. Mol Biol Evol. 2003 Mar 5;20(4):491–502. doi: 10.1093/molbev/msg034. [DOI] [PubMed] [Google Scholar]
- Malécot G. Heterozygosity and relationship in regularly subdivided populations. Theor Popul Biol. 1975 Oct;8(2):212–241. doi: 10.1016/0040-5809(75)90033-7. [DOI] [PubMed] [Google Scholar]
- Maruyama T. Rate of decrease of genetic variability in a two-dimensional continuous population of finite size. Genetics. 1972 Apr;70(4):639–651. doi: 10.1093/genetics/70.4.639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pritchard J. K., Seielstad M. T., Perez-Lezaun A., Feldman M. W. Population growth of human Y chromosomes: a study of Y chromosome microsatellites. Mol Biol Evol. 1999 Dec;16(12):1791–1798. doi: 10.1093/oxfordjournals.molbev.a026091. [DOI] [PubMed] [Google Scholar]
- Rousset F. Equilibrium values of measures of population subdivision for stepwise mutation processes. Genetics. 1996 Apr;142(4):1357–1362. doi: 10.1093/genetics/142.4.1357. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rousset F. Inbreeding and relatedness coefficients: what do they measure? Heredity (Edinb) 2002 May;88(5):371–380. doi: 10.1038/sj.hdy.6800065. [DOI] [PubMed] [Google Scholar]
- Sumner J., Rousset F., Estoup A., Moritz C. "Neighbourhood" size, dispersal and density estimates in the prickly forest skink (Gnypetoscincus queenslandiae) using individual genetic and demographic methods. Mol Ecol. 2001 Aug;10(8):1917–1927. doi: 10.1046/j.0962-1083.2001.01337.x. [DOI] [PubMed] [Google Scholar]
- Whitlock M. C., McCauley D. E. Indirect measures of gene flow and migration: FST not equal to 1/(4Nm + 1). Heredity (Edinb) 1999 Feb;82(Pt 2):117–125. doi: 10.1038/sj.hdy.6884960. [DOI] [PubMed] [Google Scholar]