Heterochromatin heterogeneity in Drosophila chromosomes detected by AluI-banding.
In situ selective digestion of mitotic chromosomes from three Drosophila species (virilis, hydei, and funebris), having a chromosome number 2n = 12, was achieved with AluI restriction endonuclease. The distribution of AluI-bands, revealing a heterogeneity within heterochromatin, was compared with that of quinacrine-bands observed in standard chromosomes. The results confirmed a species-specific AluI-banding pattern, heterochromatin being selectively digested in D. virilis and D. funebris, but unaffected by the enzyme in D. hydei. The overlapping of AluI-bands and Q-bands in D. virilis and in D. funebris is discussed, since these data seem to favour the hypothesis that the induction of AluI-bands does not depend only on the presence of enzyme targets, but also on a suitable conformation of the chromatin.
Faccio Dolfini
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Dipartimento di Genetica e di Biologia dei microrganismi, Milano, Italy.
D000818:Animals; D002871:Chromosome Banding; D002875:Chromosomes / Q000032:analysis; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics*; D006570:Heterochromatin / Q000032:analysis*
D006570:Heterochromatin; C024669:endodeoxyribonuclease AluI; D015252:Deoxyribonucleases, Type II Site-Specific