Sites of the 5s Ribosomal Genes in Drosophila. I. the Multiple Clusters in the VIRILIS Group

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RESUMO

Drosophila melanogaster 125I-5S RNA was annealed to salivary gland preparations of 6 species in the virilis group of Drosophila. Two patterns of annealing were found. D. virilis, D. montana and D. borealis showed three 5S gene clusters on chromosome 5; Sd–f and Wc–j were strongly labeled, but Xa–e was weakly labeled. D. montana and D. borealis have a greater percentage of their total 5S cistrons at S d–f than does D. virilis. D. americana americana, D. americana texana and D. novamexicana showed 2 sites labeled; no label was seen at Sd–f while Wc–j was weakly labeled and Xa–e was strongly labeled, the reciprocal of the previous pattern in the W-X region. Hybrids between D. a. americana and D. virilis showed no difference in chromosome banding at the sites of the 5S clusters despite their pattern differences. D. a texana x D. virilis, on the other hand, did show a difference in staining the Xa–e region. These patterns fall squarely into the biosystematic groupings deduced by many previous workers.

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