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Effective size of populations under selection
1Institute of Cell, Animal and Population Biology, University of Edinburgh, Scotland.
Genetics
|February 1, 1995
Summary
New equations approximate effective population size (Ne) under selection, incorporating mating systems like assortative and full-sib mating. These models aid in understanding genetic diversity and inbreeding in breeding programs.
Area of Science:
- Population Genetics
- Quantitative Genetics
- Animal Breeding
Background:
- Accurate estimation of effective population size (Ne) is crucial for managing genetic diversity and preventing inbreeding in populations undergoing selection.
- Existing models often simplify mating systems, potentially limiting their applicability to real-world scenarios with complex mating behaviors.
Purpose of the Study:
- To develop and present novel equations for approximating effective population size (Ne) that account for various mating systems, including partial full-sib and assortative mating.
- To provide a more comprehensive framework for predicting genetic drift and inbreeding under continued selection.
Main Methods:
- Derivation of general equations for Ne incorporating parameters such as family size variance, selective advantage variance, deviation from Hardy-Weinberg proportions, and genetic correlations between parents.
- Extension of the model to accommodate unequal numbers of males and females.
- Validation of the predictive accuracy of the derived formulae using a truncation selection model with an infinitesimal gene effect assumption.
Main Results:
- A general equation for Ne is presented: Ne = 4N/[2(1 - alpha I) + (Sk2 + 4Q2C2) (1 + alpha I + 2 alpha O)], where parameters quantify mating system and selection effects.
- Specific approximations for random mating and partial full-sib mating scenarios are derived.
- The proposed equations demonstrate predictive value when compared against established methods and simulation models.
Conclusions:
- The developed equations offer a more nuanced approach to estimating effective population size under selection by integrating complex mating structures.
- A novel mating strategy, 'compensatory mating,' is proposed to mitigate inbreeding rates without compromising selection response.
- These findings have significant implications for optimizing breeding programs and conserving genetic resources in managed populations.