Distribution of Spacer Length Classes and the Intervening Sequence Among Different Nucleolus Organizer in Drosophila hydei

Drosophila hydei rRNA genes from different chromosomes and from different stocks have been studied by restriction enzyme analysis. In DNA from wild-type females, about half of the X chromosomal rRNA genes are interrupted by an intervening sequence within the 28S coding region. In contrast to D. mela...

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Bibliographic Details
Published in:Chromosoma 1981-01, Vol.83 (2), p.145-158
Main Authors: Kunz, W, Petersen, G, Renkawitz-Pohl, R, Glaetzer, KH, Schaefer, M
Format: Article
Language:English
Subjects:
Drosophila hydei
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Summary:Drosophila hydei rRNA genes from different chromosomes and from different stocks have been studied by restriction enzyme analysis. In DNA from wild-type females, about half of the X chromosomal rRNA genes are interrupted by an intervening sequence within the 28S coding region. In contrast to D. melanogaster , the intervening sequences belong to a single size class of 6.0 kb. Although there are two nucleolus organizers on the Y chromosome, genes containing the intervening sequence seem to be restricted to the X chromosome. In genomic rDNA, the spacers differ in length by a regular 0.25 kb interval. Spacers with between 5 and 15 subrepeats occur frequently within the X and Y chromosomal nucleolus organizers in different D. hydei stocks; shorter and longer spacers are also present but are relatively rare. Although each genotype is characterized by different frequencies of some spacer classes, the prominent spacer length heterogeneity pattern is similar among the different nucleolus organizers and, therefore, seems to be conserved during evolution.
ISSN:0009-5915