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Seasonal but not sex-biased gene expression of the carotenoid ketolase, CYP2J19, in the sexually dichromatic southern red bishop (Euplectes orix).

Published version

Published version
Peer-reviewed

Repository DOI


Change log

Authors

Lindsay, Willow R 
Slight, Mathilda Waleij 
Andersson, Mats X 

Abstract

Intense red colours in birds are often owing to ketocarotenoids (KCs). In many land birds, KCs are oxidized from dietary yellow precursors, presumably by the avian carotenoid ketolase CYP2J19, the regulation and constraints of which have important implications for condition-dependence and honest signalling of carotenoid colour displays. We investigated hepatic CYP2J19 gene expression in the seasonally and sexually dichromatic southern red bishop (Euplectes orix) in relation to season, sex, progression of the prenuptial moult, testis size, body condition, redness and circulating sex steroids. A coloration function of CYP2J19 is supported by a seasonal upregulation prior to and during the carotenoid-depositing stage of the male prenuptial moult. However, CYP2J19 expression was similarly high in females (which do not moult prenuptially), and remained high in males after moult, suggesting additional or alternative roles of hepatic CYP2J19 or its products, such as detoxification or antioxidant functions. In males, the CYP2J19 upregulation preceded and was unrelated to the rise in plasma testosterone, but was correlated with androstenedione, probably of adrenal origin and compatible with luteinizing hormone-induced and (in females) oestrogen-suppressed moult. Finally, contrary to ideas that carotenoid ketolation rate mediates honest signalling of male quality, CYP2J19 expression was not related to plumage redness or male body condition.

Description

Peer reviewed: True


Funder: Carl Tryggers Stiftelse för Vetenskaplig Forskning; Id: http://dx.doi.org/10.13039/501100002805


Funder: Rådman och Fru Ernst Collianders Stiftelse för Välgörande Ändamål; Id: http://dx.doi.org/10.13039/501100006726


Funder: Stiftelsen Längmanska Kulturfonden; Id: http://dx.doi.org/10.13039/501100008584


Funder: Kungliga Vetenskaps- och Vitterhetssamhället


Funder: Stiftelsen Lars Hiertas Minne; Id: http://dx.doi.org/10.13039/501100004722

Keywords

CYP2J19, androstenedione, carotenoid metabolism, ketocarotenoids, plumage coloration, testosterone

Journal Title

R Soc Open Sci

Conference Name

Journal ISSN

2054-5703
2054-5703

Volume Title

Publisher

The Royal Society
Sponsorship
Swedish Research Council (2015-04800)