Infographic: Dialing Down the Glitz

The gene BCO2 enables male and female members of some bird species to display dramatically different color patterns.

Rachael Moeller Gorman

Sep 1, 2020

In some finch species, BCO2, a gene that encodes a carotenoid-destroying enzyme, is expressed in many female finch feathers but not in many male feathers. This generates dramatic sexual dichromatism that makes males dazzle while females look relatively drab. In common canaries, which are not sexually dichromatic, both males and females have little BCO2 expression in their feathers.