منابع مشابه
Crossover interference on nucleolus organizing region-bearing chromosomes in Arabidopsis.
In most eukaryotes, crossovers are not independently distributed along the length of a chromosome. Instead, they appear to avoid close proximity to one another--a phenomenon known as crossover interference. Previously, for three of the five Arabidopsis chromosomes, we measured the strength of interference and suggested a model wherein some crossovers experience interference while others do not....
متن کاملThe nucleolus.
When cells are observed by phase contrast microscopy, nucleoli are among the most conspicuous structures. The nucleolus was formally described between 1835 and 1839, but it was another century before it was discovered to be associated with a specific chromosomal locus, thus defining it as a cytogenetic entity. Nucleoli were first isolated in the 1950s, from starfish oocytes. Then, in the early ...
متن کاملThe nucleolus
Are they always about? Not necessarily. They come and go, disappearing in mitosis from late prophase until telophase. During this period, some nucleolar antigens, including RNA polymerase I and topoisomerase I, remain associated with tandemly repeated clusters of ribosomal RNA genes on the condensed chromatin — these chromosomal regions are presumptuously known as nucleolar organising regions (...
متن کاملThe Nucleolus and Parachromatin of the Ascites Tumor Cell
1. A method is described for distinguishing the ribonucleoproteins of the nucleolus and parachromatin of ascitic tumor cells of the mouse. 2. In these cells the transfer of ribonucleoprotein from the nucleus to the cytoplasm can occur in two ways. (a) At the end of prophase the nucleolus separates from the chromosomes and nucleolar fragments are released into the cytoplasm. (b) During prophase ...
متن کاملUltrastructure of the Nucleolus during the Chinese Hamster Cell Cycle
Changes in the structure of the nucleolus during the cell cycle of the Chinese hamster cell in vitro were studied. Quantitative electron microscopic techniques were used to establish the size and volume changes in nucleolar structures. In mitosis, nucleolar remnants, "persistent nucleoli," consisting predominantly of ribosome-like granular material, and a granular coating on the chromosomes wer...
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ژورنال
عنوان ژورنال: Nature
سال: 1985
ISSN: 0028-0836,1476-4687
DOI: 10.1038/318410a0