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Characteristics of the variance effective population size over time using an age structured model with variable size
Fredrik Olsson1, Ola Hössjer, Linda Laikre
1Department of Mathematics, Div. of Mathematical Statistics, Stockholm University, Stockholm, Sweden.
Theoretical Population Biology
|October 15, 2013
Summary
The variance effective population size (NeV) calculation is sensitive to how age classes are weighted. Using reproductive values as weights leads to discrepancies that diminish over longer time spans, especially in non-constant populations.
Area of Science:
- Population Biology
- Evolutionary Genetics
- Quantitative Genetics
Background:
- The variance effective population size (NeV) is crucial for understanding genetic drift.
- Accurate NeV calculation for populations with overlapping generations requires weighting age classes by reproductive value.
- Existing methods may not fully capture NeV dynamics under varying population structures.
Purpose of the Study:
- To analytically explore the impact of different age-class weighting schemes on NeV.
- To investigate how NeV reflects genetic drift variance across varying time spans and population dynamics.
- To assess the conditions under which NeV estimation using reproductive values is accurate.
Main Methods:
- Developed a novel analytical model for NeV in haploid populations with overlapping generations.
- Incorporated increasing, declining, and constant population sizes with stochastic age structure variations.
- Utilized analytical derivations and simulations to compare NeV estimates with different weighting schemes.
Main Results:
- The discrepancy between NeV calculated with reproductive values versus equal weighting approaches a constant as the time span increases.
- This constant difference is zero only for populations with constant expected size.
- The influence of overlapping generations on NeV estimation decreases with longer sampling intervals.
Conclusions:
- NeV estimation using reproductive values requires careful consideration of the time interval between samples.
- The temporal method for NeV estimation is less affected by overlapping generations over extended periods.
- The model provides a framework for assessing life history impacts on NeV and determining appropriate sampling times.
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