Abstract
The DNA in the macronucleus of the protozoan Oxytricha, unlike like that of typical eukaryotes, exists as short, gene-sized molecules. Within the macronucleus the rRNA genes are contained in molecules 7,380 nucleotide pairs in length. This rDNA has been substanially purified by selective denaturation of non-ribosomal DNA followed by Sl nuclease digestion. Results from restriction nuclease digestion and rRNA:DNA hybridization show that the rDNA is a linear, non-palindromic molecule which contains one gene each for the 19s and 25s rRNAs. A total of less than 600 base pairs of DNA lies between the 19s and 25s genes or at the 3′ end of the 25s gene. The non-coding portion of the ribosomal DNA is almost entirely limited to an approximately 1,400 base pair region at the 5′ end of the molecule.
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Spear, B.B. Isolation and mapping of the rRNA genes in the macronucleus of Oxytricha fallax . Chromosoma 77, 193–202 (1980). https://doi.org/10.1007/BF00329544
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DOI: https://doi.org/10.1007/BF00329544