Amplified ribosomal DNA in meiotic prophase oocyte nuclei of acipenserid fishes

In situ hybridization has been performed in sections through ovaries of Acipenser ruthenus and Acipenser güldenstädti in order to detect the rDNA sequences. Hybridization resulted in specific labelling of the "caps" of extrachromosomal DNA present in pachytene oocyte nuclei and of the chromatin granules distributed beneath the nuclear envelope in early diplotene nuclei. In the same sections, the nuclei of all ovarian cells in both species (oogonia, leptotene, and zygotene stage oocytes, follicular cells, connective tissue cells) showed a very low, but similar labelling. Amplification of genes for rRNA thus occurs at the pachytene stage in early oogenesis of Acipenseridae. No rDNA amplification could be detected in the previous stages. © 1979 Springer-Verlag.SCOPUS: ar.jinfo:eu-repo/semantics/publishe