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Genetic differentiation and phenotypic plasticity drive troglomorphic character development in European cavefish
Jasminca Behrmann-Godel1,2, Samuel Roch3, Alexander Böhm1
1Department of Biology, University of Konstanz, Konstanz, Germany.
Evolution; International Journal of Organic Evolution
|January 22, 2024
Summary
Evolutionary adaptation in Aach cave loach (Barbatula barbatula) shows that eye degeneration is heritable, while sensory traits exhibit plasticity. This highlights the interplay of genetics and environment in cavefish evolution.
Area of Science:
- Evolutionary Biology
- Ecology
- Genetics
Background:
- The Aach cave loach (Barbatula barbatula) is a recently discovered Nemacheilidae species.
- Cavefish offer insights into evolutionary adaptation mechanisms.
Purpose of the Study:
- To investigate the genetic and environmental influences on troglomorphic character evolution in Aach cave loach.
- To understand the roles of heritability and phenotypic plasticity in adaptation to subterranean environments.
Main Methods:
- Common garden experiment with laboratory-bred cave, surface, and hybrid loach.
- Exposure of fish to different light conditions (natural photoperiod vs. complete darkness).
- Comparative analysis of troglomorphic traits (eye size, pigmentation, barbels, olfactory epithelia).
Main Results:
- Cavefish exhibited smaller eyes, lighter pigmentation, longer barbels, and larger olfactory epithelia compared to surface fish.
- Fish reared in darkness showed convergence towards the cavefish phenotype, while cavefish in light approached the surface phenotype.
- Eye degeneration traits were primarily heritable, whereas chemo- and mechano-reception traits displayed phenotypic plasticity.
Conclusions:
- Genetic differentiation and phenotypic plasticity interact to drive troglomorphic adaptation.
- Phenotypic plasticity plays a significant role in early adaptation stages, alongside drift and selection.
- Aach cave loach provides a valuable model for studying evolutionary mechanisms in recently adapted cavefish.
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