Gaginskaya E.R., Gruzova M.N.
Detection of the amplified rDNA in ovarial cells of some insects and birds by hybridization in situ.
Tsitologiia — 1975. — V. 17, — P. 1132–1137.

Sections of ovaries of two insects (Chrysopa peria L. and Laspeyresia pomonella L.) and of two birds (Columba livia L. and Fringilla coelebs L.) were used for nucleic acid hybridization experiments in situ (after Gall and Pardue, 1969; 1971). The total 28S and 18S H3-rRNA of Drosophila was taken for hybridization. After the procedure of hybridization the labeling was seen over the oocyte nuclei and in the nucleus of one of seven trophocytes (originating from a pro-oocyte) in each egg camera of the Ch. peria ovary. The localization of silver grains was well comparable with that of bodies and clumps of the extrachromosomal DNA. The label was also observed over sex chromatin bodies and over the complex nucleoli in the trophocytes of L. pomonella. No label was actually seen in the oocyte nuclei of L. pomonella and of both the avian species which lack the true nucleoli. The evidence provided establish the ribosomal origin of DNA bodies in the oocyte, and in one of the trophocytes of Ch. peria. In addition, the participation of ribosomal genes in the formation of sex chromatin bodies in the trophocytes of L. pomonella was established. At the same time the absence of amplified ribosomal genes was demonstrated in the oocytes of L. pomonella and the birds.