Sexual dichromatism, characterized by sex-specific differences in coloration, is widespread among birds and often involves carotenoid-based pigmentation. Despite extensive research on the social and ecological environments favoring sexual dichromatism, the molecular mechanisms underlying its development and evolution remain largely unexplored.
I am part of a collaborative study investigating the genetic and molecular processes underlying sexual dichromatism in the red ketocarotenoid-based plumage coloration of northern cardinals (Cardinalis cardinalis).
We quantified carotenoid concentrations in plasma and feather follicles, confirmed that homologs of CYP2J19, BDH1L, and TTC39B catalyze the addition of a keto group at C4, and performed gene expression analyses across tissues.
Our findings indicate that sex-specific regulation of carotenoid processing genes underpins the vivid red coloration in males and the drab phenotype in females, likely maintained by a balance between natural and sexual selection, with mechanisms of sexual antagonism affecting divergent gene expression.
Paper to come soon (hopefully!)
Featured image (c) Clarence Stewart
'Omics in the Anthropocene 