Visualization of Nucleolar Genes

Science  23 May 1969:
Vol. 164, Issue 3882, pp. 955-957
DOI: 10.1126/science.164.3882.955


The presence of extrachromosomal nucleoli in amphibian oocytes has permitted isolation and electron microscopic observation of the genes coding for ribosomal RNA precursor molecules. Visualization of these genes is possible because many precursor molecules are simultaneously synthesized on each gene. Individual genes are separated by stretches of DNA that apparently are not transcribed at the time of synthesis of precursor rRNA in the extrachromosomal nucleoli.

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