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Updated: Jun 3, 2026
08:02
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
Strong and consistent natural selection associated with armour reduction in sticklebacks.
Arnaud LE Rouzic1, Kjartan Østbye, Tom O Klepaker
1Department of Biology, Center for Ecology and Evolutionary Synthesis, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway. lerouzic@legs.cnrs-gif.fr
Molecular Ecology
|March 30, 2011
Summary
Natural selection drives rapid evolution in threespine stickleback fish adapting to freshwater. Freshwater-type fish showed a significant fitness advantage, highlighting rapid adaptation to environmental change.
Area of Science:
- Evolutionary Biology
- Ecology
- Genetics
Background:
- Measuring natural selection is crucial but difficult.
- Threespine stickleback (Gasterosteus aculeatus) exhibit parallel evolution of reduced lateral plates during freshwater adaptation.
- The Ectodysplasin-A (Eda) locus is key to armour development.
Purpose of the Study:
- To analyze selection on a morphological change (lateral-plate reduction) in threespine stickleback.
- To quantify the fitness advantage of freshwater-type fish.
- To understand rapid phenotypic evolution driven by environmental change.
Main Methods:
- Introduced completely-plated and low-plated sticklebacks into a pond.
- Tracked phenotypic changes over 20 years.
- Genotyped the Ectodysplasin-A (Eda) locus in the final generation.
Main Results:
- Freshwater-type fish had a substantial fitness advantage (20% for morph, 92% for genotype).
- Fitness advantage likely highest at invasion onset, decreasing over time.
- Demonstrated rapid, selection-driven phenotypic evolution linked to environmental change.
Conclusions:
- Quantifiable evidence of strong natural selection favoring freshwater adaptation in sticklebacks.
- The Eda locus plays a significant role in adaptation to new environments.
- This study provides a model for understanding rapid evolutionary responses in natural populations.
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