Sex determination driven by community cooperation

An optimized ratio of male and females in a sexually reproducing population helps to generate the genetic diversity useful to a species in a changing world. Tanaka et al. studied a fern in which the sex ratio is adjusted not by individual identity, but by signaling between individual plants (see the Perspective by Sun). Early-maturing individual ferns express some of the biosynthetic genes needed to make a precursor of the plant hormone gibberellin, which they secrete into the environment. Younger ferns, which express the enzymes needed to finalize synthesis of gibberellin, take up the signal and in response develop the organs that produce male gametes.

Science, this issue p. 469; see also p. 423