This yielded 94 associated genes whose expression was significantly similar in distribution to cyclin D1. Included in this list were several ribosomal protein genes and other known RPC expressed genes such as Fgf15. The relative expression levels for each of these genes and scaled scores were calculated. Upon inspection, however, the Magnoflorine-iodide distribution of these scores was observed to be very narrow owing to the high levels of expression for many of these genes in the profiled single cells and the persistence of many of these transcripts in newborn neurons. Therefore, to improve the classification of cycling RPCs,Tenacissoside-X additional gene clusters were added to generate a composite RPC score. To generate a composite RPC classification score, three additional genes were chosen to generate gene clusters. These genes have been observed previously in the outer neuroblastic layer of the retina, where the RPCs reside. These 3 genes were also chosen as they together accommodate some of the temporal heterogeneity of the RPCs, as described below. Using the Fisher’s exact test and a cutoff p-value of 1023 as before, associated genes were identified for each of these three genes. The relative expression levels were calculated and scaled RPC scores generated. As shown in Figure 1, 42 cells displayed a significant RPC score. For 36 of these cells, this score was considerably higher than that for RGC, AC, or PR, establishing these single cell profiles as coming from cycling RPCs. These cells are most likely transitional cells, RPCs that are in the process of generating a postmitotic daughter and a full analysis of their gene expression will be presented elsewhere. Since transcripts expressed in RPCs would not be expected to disappear immediately, it was predicted that some cells would possess profiles containing genes expressed in one or more neuronal cell types, together with RPC genes that are in the process of being downregulated. Such transitional cells are of interest as they provide a window into cells that might still be in the process of deciding upon a final fate. If this state was plastic, it might be revealed through the expression of markers of multiple neuronal cell types.