FST and genetic diversity in an island model with background selection.

Area of Science:

• Evolutionary genetics
• Population genetics theory

Background:

• Background selection reduces genetic diversity at linked neutral sites.
• Theory currently quantifies effects only for deleterious alleles under strong selection.
• Migration's impact on background selection's effect on FST remains unclear.

Purpose of the Study:

• To derive novel theory for migration's effects on background selection in subpopulations.
• To extend existing theory for interference selection into structured populations.
• To predict effects on neutral diversity (πT) and genetic differentiation (FST) in an island model.

Main Methods:

• Derivation of novel population genetics theory.
• Extension of existing interference selection theory.
• Simulations to test theoretical predictions against FST and πT.

Main Results:

• The derived theory accurately predicts FST and πT.
• High migration rates lead to minimal increases in FST due to reduced correlated fitness effects.
• Background selection substantially reduces πT, particularly in large metapopulations.

Conclusions:

• Novel theory extends background selection into structured populations.
• Background selection minimally confounds locus-to-locus FST scans under high migration.
• Understanding background selection is crucial for interpreting population genetic data.