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Selection for Tameness in Red Junglefowl Recapitulates Genetic Loci Associated With Domestication-Related Brain
Carlos Guerrero-Bosagna1, Fábio Pértille1, Zahra Moradinour2
1Physiology and Environmental Toxicology Program, Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, Uppsala, Sweden.
Molecular Ecology
|May 19, 2025
Summary
Selection for tameness in chickens (Gallus gallus) influences brain composition and anxiety. This suggests tameness may be the primary driver of the domestication syndrome.
Area of Science:
- Animal genetics
- Evolutionary biology
- Behavioral genetics
Background:
- Domestication leads to significant phenotypic changes, known as the Domestication Syndrome.
- Key traits include reduced fear of humans (tameness) and altered brain composition.
Purpose of the Study:
- To investigate the genetic basis of tameness and its relationship with brain composition in early domestication.
- To determine if selection for tameness drives core domestication traits.
Main Methods:
- Created two Red Junglefowl lines bidirectionally selected for fear of humans over eight generations.
- Developed an intercross population from these selection lines.
- Utilized genome-wide mapping and between-line analysis to identify genetic loci.
Main Results:
- Genetic loci for tameness co-localized with loci for brain composition and anxiety behavior.
- Brain composition loci overlapped with those found in a separate wild x domestic chicken cross.
- Tameness and brain composition appear to be genetically linked or pleiotropic.
Conclusions:
- Selection for tameness may be the initial evolutionary pressure in domestication.
- This selection pressure recapitulates genetic loci targeted by broader domestication.
- Tameness selection could be the foundational element of the Domestication Syndrome.
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