Repeated dna and heterochromatin structure in rumex acetosa

Abstract

Seven clones, six of which represent moderate to highly repeated sequences, were isolated from a plasmid clone bank of EcoRI-digested Rumex acetosa DNA. All sequences revealed a dispersed nature when chromosomes were probed by in situ hybridization. Studies of RNA transcription by these sequences indicate that one, pRal41, may be actively transcribed. The implications of these results on the current understanding of the nature of the chromatin in the R. acetosa Y chromosome are discussed. Preliminary evidence is produced for a facultative heterochromatic sex system in plants. © 1993 The Genetical Society of Great Britain.