The Spread of an Inversion with Migration and Selection.

Area of Science:

• Population genetics
• Evolutionary biology
• Genomics

Background:

• The Kirkpatrick and Barton model explains how selection maintains alleles in a population despite gene flow.
• Understanding the role of inversions in maintaining genetic diversity is crucial.

Purpose of the Study:

• To re-examine the model of Kirkpatrick and Barton regarding the spread of inversions.
• To investigate the selective advantage of inversions in preventing the breakdown of linkage disequilibrium due to migration.

Main Methods:

• Mathematical modeling of population genetics.
• Derivation of expressions for the rate of inversion spread.
• Analysis of the relationship between inversion advantage and recombination rates.

Main Results:

• Inversions are favored because they preserve linkage disequilibrium disrupted by migration.
• The selective advantage of an inversion is inversely related to the recombination rate between the involved loci.
• When loci are tightly linked within an inversion, its advantage is significantly reduced compared to previous models.

Conclusions:

• Inversions play a key role in maintaining genetic variation by counteracting homogenizing gene flow.
• The rate of spread and selective advantage of inversions are strongly influenced by recombination dynamics.
• Previous models may overestimate the advantage of inversions when linked loci are involved.