Worm Breeder's Gazette 8(3): 69
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have determined the complete nucleotide sequence of one ribosomal DNA tandem repeat (that cloned originally by J. Files and D. Hirsh as pCe7). Furthermore, in comparing this data with partial sequence data obtained from three separately isolated rDNA clones, we have seen almost no sequence variation, indicating the highly homogeneous nature of the rDNA repeat population in C. elegans. Preliminary examination of the sequence has confirmed the size and location of the genes for each of the rRNA species produced, as predicted by visualization of R- loops (Files and Hirsh). The 26s and 18s rDNA genes each show the expected pattern of several long stretches of sequence very homologous to that in the rDNA of other eukaryotic organisms, interrupted by short regions with no significant homology. The 5.8s rDNA gene has also been located, and the sequence of its RNA product shows the expected pairing between its 3' end and the 5' end of the 26s rRNA. We are currently running a more detailed study of the relationships between the 26s, 18s, and 5.8s rRNA molecules of C. elegans, as inferred from this sequence, and those of other eukaryotes, especially as this relates to the secondary structure of these molecules.