Identifying Y candidate genes

The circadian clock generates biological rhythms with a period of approximately 24 hours. Using microarray experiments, we have previously shown that approximately 16% of the Arabidopsis genome is regulated in a circadian manner (Edwards et al., 2006). Previous work from our lab in modelling the molecular oscillator of Arabidopsis introduced a hypothetical component Y into an evening loop of the clock gene network (Locke et al., 2005). GIGANTEA (GI) was suggested as a strong candidate for Y based on genetic evidence and its close matching of the expression profile predicted by the mathematical modelling. Recent experimental evidence suggests that GI may only partially account for the function of Y. Thus, we are undertaking a genomics approach to identify other candidate genes that match the predicted expression profile of Y. Samples were taken from wild type and lhy cca1 double mutant seedlings from 4 timepoints around the night to day transition (-15mins, +15mins, +30mins and +60mins) after 9 days of growth in 18:6 light dark cycles. We aim to identify genes showing the light induction response predicted for Y around dawn. 16 samples were used in this experiment.