The development of a large nucleolus during oogenesis in Acanthocyclops vernalis (Crustacea, Copepoda) and its possible relationship to chromatin diminution.
The development of a single, very large (25-35 microns diameter) nucleolus during oogenesis in the crustacean Acanthocyclops vernalis is described. The nucleolus is the site of ribosomal RNA production in the egg, as shown by in situ hybridization, and apparently the only source, as accessory cells are not observed. Ribosomal DNA amplification, as manifested by the presence of multiple nucleoli, is also not observed. Silver staining and C-banding suggest that chromosomal regions other than the nucleolar organizer are involved with the elaboration of the nucleolus. These observations, along with what is known about the nature of the DNA lost during the developmental process of chromatin diminution in this organism, suggest a relationship between the large oocyte nucleolus and the DNA lost during diminution.
Standiford
D M
DM
Department of Zoology, Miami University, Oxford, OH 45056.
D000818:Animals; D002466:Cell Nucleolus / Q000648:ultrastructure*; D002843:Chromatin / Q000502:physiology / Q000648:ultrastructure*; D002871:Chromosome Banding; D003445:Crustacea / Q000502:physiology*; D004247:DNA / Q000032:analysis; D005260:Female; D009693:Nucleic Acid Hybridization; D009866:Oogenesis; D010053:Ovary / Q000166:cytology; D012834:Silver; D013194:Staining and Labeling
D002843:Chromatin; D012834:Silver; D004247:DNA