Brain size is reduced by selection for tameness in Red Junglefowl – correlated effects in vital organs.
Open accessAbstract
During domestication animals have undergone changes in size of brain and other vital organs. We hypothesize that this could be a correlated effect to increased tameness. Red Junglefowl (ancestors of domestic chickens) were selected for divergent levels of fear of humans for five generations. The parental (P0) and the fifth selected generation (S5) were culled when 48-54 weeks old and the brains were weighed before being divided into telencephalon, cerebellum, mid brain and optic lobes. Each single brain part as well as the liver, spleen, heart and testicles were also weighed. Brains of S5 birds with high fear scores (S5 high) were heavier both in absolute terms and when corrected for body weight. The relative weight of telencephalon (% of brain weight) was significantly higher in S5 high and relative weight of cerebellum was lower. Heart, liver, testes and spleen were all relatively heavier (% of body weight) in S5 high. Hence, selection for tameness has changed the size of the brain and other vital organs in this population and may have driven the domesticated phenotype as a correlated response.
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Selection for tameness in chickens produces several reproductive and physiological changes similar to those found in the mammalian domestication syndrome.
“Selection for tameness in chickens Gallus gallus domesticus also produces several reproductive and physiological changes similar to those found in the mammalian domestication syndrome (Agnvall et al., 2017).”
From Hypotheses for the Evolution of Reduced Reactive Aggression in the Context of Human Self-Domestication (2019) · cites this paper as Agnvall et al., 2017
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- Authors
- Agnvall, B., Bélteky, J., & Jensen, P.
- Affiliations
- Linköping University (SE)
- Corresponding author
- Jensen, Per
- Venue
- Scientific Reports
- Published
- 2017-06-12
- Volume
- 7
- Issue
- 1
- Pages
- 3306-3306
- ISSN
- 2045-2322 (ISSN-L)
- PMC
- PMC5468340
- OpenAlex
- W2621702433
- Cited by
- 36
- References
- 38
- Citations by year
- 2025: 5 · 2024: 2 · 2023: 2 · 2022: 6 · 2021: 6 · 2020: 7 · 2019: 4 · 2018: 3 · 2017: 1
- FWCI
- 3.56
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- Scientific Reports (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, other-oa)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- KTH Publication Database DiVA (KTH Royal Institute of Technology) (submittedVersion, other-oa)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Svenska Forskningsrådet Formas
- FP7 Ideas: European Research Council (322206)
- Topics
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic and phenotypic traits in livestock
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Human-Animal Interaction Studies
- Keywords
- brain size, tameness, red junglefowl, domestication, fear of humans, divergent selection, telencephalon, cerebellum, organ size, correlated effects, chickens
- MeSH terms
- Animals, Animals, Domestic, Brain, Fear, Female, Humans, Male, Organ Size, Poultry, Selection, Genetic
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