Domestication effects on crowing in chickens: variation between wild and captive red junglefowl and domestic white Leghorn and the genetic architecture of crowing vocalizations.

The crowing of the male chicken is a charismatic example of vocal display in a bird. It is regarded as the main territorial announcement of the ancestral red junglefowl. The call has been preserved throughout domestication, although several of its elements have been altered. To assess these alterations, we assayed crowing spectrograms from wild and captive-held red junglefowl populations from India, along with two red junglefowl populations held in long-term captivity in Sweden, and a domestic white Leghorn breed. We find consistent differences between the different Indian red junglefowl and the domestic white Leghorn for a range of characteristics, including the duration of the last syllable and the number of formants and their frequency in the last and second-to-last syllable. To analyse the genetic architecture of crowing vocalization, we performed a quantitative trait loci (QTL) experiment using a wild × domestic advanced intercross to identify QTL that explained a large percentage of the variation present for the duration of the last syllable and the number of formants in the second to last syllable. With this study we thus demonstrate consistent differences in red junglefowl and white Leghorn chickens and identify a relatively simple genetic architecture for some of these traits.This article is part of the theme issue 'Unravelling domestication: multi-disciplinary perspectives on human and non-human relationships in the past, present and future'.