12 June 2020
Vol 368, Issue 6496

About The Cover

Cover image expansion

COVER Male (left) and female (right) canaries (Serinus canaria) exhibiting sexual dichromatism—i.e., color difference between sexes. These mosaic canaries were created by crossing common canaries with red siskins and selecting the progeny for sexual dichromatism. The pronounced differences in plumage coloration are driven by a single gene that mediates sexual dichromatism in birds. See pages 1185 and 1270.
Photo: Ricardo Jorge Lopes