ABOVE: A European serin
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The paper
M. Gazda et al., “A genetic mechanism for sexual dichromatism in birds,” Science, 368:1270–74, 2020.
Male red siskins (Spinus cucullatus), a species of finch, flaunt orange-red bellies and backs, contrasting with their black heads and dark wing markings. The females, on the other hand, are mostly muted shades of grey (though pops of orange-red and black do appear on their bellies and wings). Such differences in coloration between the sexes, called sexual dichromatism, occur in many bird species, but their root cause has confounded scientists for years.
Geneticist Miguel Carneiro of the Research Centre in Biodiversity and Genetic Resources (CIBIO) at the University of Porto in Portugal had previously discovered that a siskin gene called CYP2J19 encodes an enzyme that helps convert yellow carotenoid compounds from seeds in the birds’ diet into the red carotenoids found in their feathers. But he wanted ...
