The genetic basis for PRC1 complex diversity emerged early in animal evolution
James M. Gahan, Fabian Rentzsch, Christine E. Schnitzler
Abstract
Significance Animals, to maintain patterns of gene expression throughout life, utilize the Polycomb system to repress transcription. Vertebrates have a large number of Polycomb protein complexes, particularly belonging to the Polycomb Repressive Complex 1 (PRC1) family. Here we show that, contrary to current hypotheses, the large number of complexes found in vertebrates appeared early in animal evolution and was subsequently reduced in many lineages. Among the species studied here, only anthozoan cnidarians (corals and sea anemones) and vertebrates have the full set of possible PRC1 complexes and therefore it will be interesting to study their function in these animals. This study highlights the importance of nonstandard model organisms when studying the evolution of processes such as gene silencing by Polycomb.