Toyota, K. (Grad. Univ. Advanced Studies), Miyakawa, H., Oda, S., Miyagawa, S., Ogino, Y. (Natl. Inst. Basic Biol.), Tatarazako, N. (Natl. Inst. Environ. Studies), Kato, Y. (Osaka Univ.), Iguchi, T. (Natl. Inst. Basic Biol.)

The water flea Daphnia magna is a common inhabitant in fresh water ponds, and switches its survival strategy from asexual to sexual reproduction, depending on habitat environmental conditions; shortened day length, decrease in food concentration and/or increase in population density. Recently, our group found that juvenile hormone (JH) or its analogs can induce male production in cladoceran crustaceans without environmental cues. Moreover, we identified doublesex (dsx) as an indispensable factor for male traits development of D. magna. However, signaling pathway of JH and regulation of dsx expression has not been elucidated. To identify JH signal transduction and its downstream pathway, we performed the global gene expression analysis of JH-responsive genes, which involved in sex determination. Several genes which function is unknown were identified as candidates for novel JH target gene.