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Published on: August 19, 2021
Statistical properties of the site-frequency spectrum associated with lambda-coalescents
Matthias Birkner1, Jochen Blath, Bjarki Eldon
1Institut für Mathematik, Johannes-Gutenberg-Universität, 55099 Mainz, Germany.
Genetics
|September 13, 2013
Summary
This study analyzes the statistical properties of the site-frequency spectrum in Λ-coalescents, developing methods to estimate population genetics parameters from large DNA sequence datasets.
Area of Science:
- Population Genetics
- Computational Biology
- Statistical Genetics
Background:
- The site-frequency spectrum is crucial for understanding population genetic processes.
- Kingman's coalescent model is a foundational tool, but limitations exist for complex scenarios.
- Λ-coalescents offer a more flexible framework for modeling population history.
Purpose of the Study:
- To derive statistical properties of the site-frequency spectrum for Λ-coalescents.
- To develop methods for estimating coalescent parameters from large datasets where traditional likelihood methods are infeasible.
- To investigate the utility of pseudolikelihood inference for distinguishing between different Λ-coalescent models.
Main Methods:
- Derivation of recursions for the expected value, variance, and covariance of the site-frequency spectrum.
- Application of expected values to estimate parameters by fitting observed spectra.
- Development and application of a pseudolikelihood inference framework.
- Analysis of simulated and real mtDNA data from Atlantic cod (Gadus morhua).
Main Results:
- Recurrence relations for the expected site-frequency spectrum were established, extending Kingman's coalescent results.
- A pseudolikelihood approach was successfully applied to estimate coalescent parameters for specific Λ-coalescent subclasses.
- The methods demonstrated the ability to differentiate between Kingman coalescents and two subclasses of Λ-coalescents, and between the Λ-subclasses themselves, even with moderate sample sizes.
Conclusions:
- The derived statistical properties and pseudolikelihood method provide effective tools for estimating coalescent parameters in large population genetic datasets.
- The study successfully distinguishes between different Λ-coalescent models, offering insights into population structure and history.
- These advancements are valuable for analyzing complex demographic histories in various species, including empirical data from Atlantic cod.
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