Ring chromosomes and rDNA magnification in Drosophila.

Journal Article (Journal Article)

Tartof showed that ribosomal gene magnification in Drosophila was inhibited in a ring X chromosome. The present studies extend this observation by showing that ring X chromosomes are lost meiotically in male Drosophila undergoing ribosomal gene magnification as evidenced by the recovery of a lower number of ring-bearing progeny under magnifying conditions compared with nonmagnifying conditions. Associated with ring chromosome loss is a highly significant increase in the number of double-sized dicentric ring chromosomes in meiotic cells from magnifying males. These observations explain the failure of ring X chromosomes to magnify and imply that magnification in rod chromosomes occurs via a mechanism of unequal sister chromatid exchange. Our results support the hypothesis that the primary event of magnification is a sister chromatid exchange in the rDNA, that the frequency of sister strand exchanges is increased in magnifying flies, that a significant number of exchanges in magnifying flies occurs meiotically and that some of the exchanges are nonreciprocal. We have also found that autosomal mutations can affect both the frequency of abnormal ring structures and the ability of ring X chromosomes to magnify.

Full Text

Duke Authors

Cited Authors

  • Endow, SA; Komma, DJ; Atwood, KC

Published Date

  • December 1984

Published In

Volume / Issue

  • 108 / 4

Start / End Page

  • 969 - 983

PubMed ID

  • 6439601

Pubmed Central ID

  • PMC1224277

International Standard Serial Number (ISSN)

  • 0016-6731

Digital Object Identifier (DOI)

  • 10.1093/genetics/108.4.969


  • eng

Conference Location

  • United States