Zebrafish produce sunscreen to protect their embryos from UV light

Zebrafish eggs contain a sunscreen called gadusol that protects the growing embryo from harmful rays.

The ultraviolet rays in sunlight are damaging. To shield against this, vertebrates produce a pigment called melanin. In aquatic vertebrates, like fish, melanin is produced by cells called melanophores. But melanophores appear late in embryonic development, so it wasn’t known what protects vulnerable fish embryos before this point.

To investigate, James Gagnon at the University of Utah …