Figure 4

Comparison of expression score ranks and posterior ranks. (a) The expression score rank and posterior rank for fission-yeast genes. The x-axis is the expression score rank (the lower the rank the more cyclic the gene is determined to be by the scoring method) and the y-axis is the rank based on our method (again, the lower the better). As can be seen, the ranks for most of the genes do not change much. The red dashed line represents the posterior threshold used to select cycling genes, and the green dashed line is the corresponding threshold if only expression scores are used. Almost all genes that are elevated by our method to a cyclic status have a rather high cyclic expression score (though some are not as high as the cutoff for score alone, which is where the two methods differ). Five selected genes are highlighted by red circles. These genes would have been missed if only expression scores were used to determined cyclicity, because their scores would be just below the cutoff. While Jensen et al. [14] do not assign cyclic status to these genes, sam1 was also identified as cycling by Peng et al. [5], SPBC17D11.08 was included in the list by Rustici et al. [4], and rpb9 was identified by both Oliva et al. [6] and Peng et al. [5]. The other two genes, SPBP8B7.26 and rmi1, are missing from all three studies, even though their profiles appear cyclic (not shown). (b-d) Similar plots for (b) budding yeast [2,3], (c) human [7], and (d) Arabidopsis [39].