Abstract
Unambiguous evidence is presented that two X-chromosome inversions produce lethality in X/O males because of position-effect suppression of genes in the basal heterochromatin. The data support the hypothesis that the ribosomal RNA cistrons are the genes suppressed. There is evidence for a region in the X basal heterochromatin that may act as a regulator of rDNA activity.
Keywords: X-chromosome inversions, viability index, gene order, chromosome
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- Baker W. K. Position-effect variegation. Adv Genet. 1968;14:133–169. [PubMed] [Google Scholar]
- COOPER K. W. Cytogenetic analysis of major heterochromatic elements (especially Xh and Y) in Drosophila melanogaster, and the theory of "heterochromatin". Chromosoma. 1959;10:535–588. doi: 10.1007/BF00396588. [DOI] [PubMed] [Google Scholar]
- LEWIS E. B. The phenomenon of position effect. Adv Genet. 1950;3:73–115. doi: 10.1016/s0065-2660(08)60083-8. [DOI] [PubMed] [Google Scholar]
- RITOSSA F. M., SPIEGELMAN S. LOCALIZATION OF DNA COMPLEMENTARY TO RIBOSOMAL RNA IN THE NUCLEOLUS ORGANIZER REGION OF DROSOPHILA MELANOGASTER. Proc Natl Acad Sci U S A. 1965 Apr;53:737–745. doi: 10.1073/pnas.53.4.737. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ritossa F. M., Atwood K. C., Spiegelman S. A molecular explanation of the bobbed mutants of Drosophila as partial deficiencies of "ribosomal" DNA. Genetics. 1966 Sep;54(3):819–834. doi: 10.1093/genetics/54.3.819. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sandler L. The Regulation of Sex Chromosome Heterochromatic Activity by an Autosomal Gene in DROSOPHILA MELANOGASTER. Genetics. 1970 Mar;64(3-4):481–493. doi: 10.1093/genetics/64.3-4.481. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tartof K. D. Increasing the multiplicity of ribosomal RNA genes in Drosophila melanogaster. Science. 1971 Jan 22;171(3968):294–297. doi: 10.1126/science.171.3968.294. [DOI] [PubMed] [Google Scholar]

