The M/G1 clusters. The transcription profiles are displayed as described in the legend to Figure Figure1.1. (A) MCM cluster. The MCM genes are involved in initiation of DNA replication and are coregulated during the M/G1 transition of the cell cycle. (B) SIC1 cluster. Twenty-seven genes that peak at the M/G1 boundary form a subcluster. (C) MAT cluster. This is a cluster of 13 coregulated genes expressed at the M/G1 boundary, many of which are involved in mating.