Mutations in Two Independent Pathways Are Sufficient to Create Hermaphroditic Nematodes

Abstract

Life Histories to Suit Nematode worms can profoundly manipulate their life histories in several ways. For example, Caenorhabditis elegans has two genders: males and hermaphrodites. Some clues for the evolution of this peculiar mating system have been revealed by Baldi et al. (p. 1002 ), who turned females of a related species, Caenorhabditis remanei , into hermaphrodites by modifying a gene involved in making sperm and another gene required for activating the spermatids. In most animals, the germ line is fully established during adulthood and a reproductive period is determined, at least in part, by aging of the germ line and the viability of oocytes. The reproductive longevity of hermaphrodite C. elegans can be increased at least 15-fold by starvation. Angelo and Van Gilst (p. 954 , published online 27 August; see the Perspective by Ogawa and Sommer ) found that in starved worms, the germline component of the reproductive system is actively killed, with the exception of a small set of preserved stem cells. When the worms are able to feed again, these cells regenerate into an entirely new and functional germ line. But this is not all. Kim et al. (p. 994 , published online 1 October; see the Perspective by Ogawa and Sommer ) show that subsets of the complex mixture of structurally related molecules in dauer pheromone act via distinct G protein–coupled receptors either to initiate longterm effects on development and physiology by modulating the neuroendocrine axis, or to trigger short-term acute effects on behavior by altering neuronal responses.