[Location of nucleolar organizers in somatic nuclei of newly-formed ovary of Japanese quail (Coturnix coturnix japonica)].

The localization of nucleolar organizers has been studied in the nuclei of the somatic cells of one-day-old quail ovaries with in situ hybridization techniques. In these cells the nucleolus apparatus has a chromocentre formed by heterochromatin and small nucleoli typified by cytochemical and ultrastructural characteristics, associated at the periphery of the chromocentre. After hybridization wtih [3H] rRNA (28 S-18 S) and histoautoradiography, levels of radioactivity are detected only on the nucleoli, and not located on the chromocentre. In the interphasic nuclei of these cells, the ribosomal cistrons are intricated with nucleolus ribonucleoproteins.