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Updated: May 30, 2026
04:52
Following the Dynamics of Structural Variants in Experimentally Evolved Populations
Published on: February 3, 2023
Adaptive chromosomal divergence driven by mixed geographic mode of evolution
Jeffrey L Feder1, Richard Gejji, Thomas H Q Powell
1Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA. feder.2@nd.edu
Evolution; International Journal of Organic Evolution
|July 28, 2011
Summary
Chromosomal inversions drive adaptation and speciation. A mixed geographic model, combining isolation and gene flow, explains how these inversions spread by natural selection, preserving beneficial gene combinations.
Area of Science:
- Evolutionary Biology
- Genetics
- Population Genetics
Background:
- Chromosomal inversions are widespread and crucial for understanding adaptation and speciation.
- Historically, inversions revealed population genetic structure and led to theories on coadapted gene complexes, founder effects, and genetic drift.
- A comprehensive theory for the origin and distribution of inversions remains incomplete.
Purpose of the Study:
- To investigate the origins and distribution of chromosomal inversions in natural populations.
- To test a novel hypothesis for inversion evolution using computer simulations.
- To explain patterns in the geographic distribution of inversions.
Main Methods:
- Utilized computer simulations to model evolutionary processes.
- Implemented a "mixed geographic mode" involving allopatric separation followed by secondary contact and gene flow.
- Analyzed the role of natural selection in the establishment of inversions.
Main Results:
- The "mixed geographic mode" promotes chromosomal divergence by natural selection under broader conditions than prior hypotheses.
- Inversions originating in allopatry carry locally adapted genes, which are preserved by reduced recombination during secondary contact.
- This mechanism facilitates the rapid establishment of inversions to high frequencies.
Conclusions:
- The proposed "mixed geographic mode" can account for observed patterns in inversion distribution.
- Selection on standing genetic variation enables rapid chromosomal evolution without requiring new mutations.
- Inversion differences likely play a significant role in the divergence of closely related taxa.
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