Polycomb group (Pc-G) genes are needed to maintain expression patterns of the homeotic selector genes of the Antennapedia (Antp-C) and Bithorax (Bx-C) complexes, and hence for the maintenance of segmental determination. Can act as a modifier of position effect variegation (PEV). During S-phase in early embryogenesis. Colocalizes with PCNA in polytene nuclei during embryogenesis. Ubiquitously expressed throughout embryonic development. High expression is detected in CNS and gonads. Expressed both maternally and zygotically. Belongs to the cramped family.