The Epigenetic Gene
Another gene that affects the photoperiod pathway is FWA. fwa mutants are gain of function epigenetic mutants, which delay flowering in long-day photoperiods (Koornneef et al., 1991; Soppe et al., 2000) . The mutation has a similar effect to that of ft mutations, suggesting that they impair a related step in flowering control (Soppe et al., 2000) . In wild-type plants, FWA is only expressed in the developing seed suggesting that it is not a flowering time gene per se, but has a role in endosperm development (Kinoshita et al., 2004) , and that the mutation delays flowering by mainly ectopic expression of FWA. The C-terminal of FWA has been shown to interact with FT in vitro (Ikeda., 2004). FWA may be able to repress the interaction between FT and FLOWERING LOCUS D (FD), which is proposed to be required for flowering and is described in section 1.7.2 (Ikeda et al., 2004) .
Repressors of flowering
Two repressors of thephotoperiod flowering-time pathway are FLM and SHORT VEGETATIVE PHASE (SVP) (Hartmann et al., 2000; Ratcliffe et al., 2001; Scortecci et al., 2001) . It is thought that these two genes act in the same pathway and that the photoperiod alleviates FLM repression (Scortecci et al., 2003) . Although FLM is closely related to FLC it is not vernalisation responsive (Ratcliffe et al., 2001) . flm mutants are able to suppress the late flowering phenotype of co and gi mutants in a dose-dependent manner, strongly suggesting that FLM acts downstream of these two genes (Scortecci et al., 2003) .
Forward to Autonomous pathway