Domestication and tameness: brain geneexpression in red junglefowl selected for less fear of humans suggests effects on reproduction and immunology
2016 (English)In: Royal Society Open Science, ISSN 2052-3068, E-ISSN 2046-2069, no 3, 160033Article in journal (Refereed) Published
The domestication of animals has generated a set of phenotypicmodifications, affecting behaviour, appearance, physiologyand reproduction, which are consistent across a range ofspecies. We hypothesized that some of these phenotypes couldhave evolved because of genetic correlation to tameness,an essential trait for successful domestication. Starting froman outbred population of red junglefowl, ancestor of alldomestic chickens, we selected birds for either high or lowfear of humans for five generations. Birds from the fifthselected generation (S5) showed a divergent pattern of growthand reproduction, where low fear chickens grew larger andproduced larger offspring. To examine underlying geneticmechanisms, we used microarrays to study gene expressionin thalamus/hypothalamus, a brain region involved in fearand stress, in both the parental generation and the S5. Whileparents of the selection lines did not show any differentiallyexpressed genes, there were a total of 33 genes with adjustedp-values below 0.1 in S5. These were mainly related to spermfunction,immunological functions, with only a few known tobe relevant to behaviour. Hence, five generations of divergentselection for fear of humans produced changes in hypothalamicgene expression profiles related to pathways associated withmale reproduction and to immunology. This may be linked to the effects seen on growth and size of offspring. These results support the hypothesis thatdomesticated phenotypes may evolve because of correlated effects related to reduced fear of humans.
Place, publisher, year, edition, pages
Royal Society Publishing , 2016. no 3, 160033
artificial selection, gene expression, microarray, chicken, fearfulness
IdentifiersURN: urn:nbn:se:liu:diva-130501DOI: 10.1098/rsos.160033OAI: oai:DiVA.org:liu-130501DiVA: diva2:952057