Skip to main content
SpringerLink
Log in

Branched chromosomes as symmetrical duplications

  • Published:
Journal of Genetics Aims and scope Submit manuscript

Summary

1. The bulb of theX-chromosome ofD. melanogaster and branched chromosomes in general are interpreted to be symmetrical duplications formed by a continuous unbranched chromonema.

2. An explanation of the formation of symmetrical duplications is advanced, and evidence for a single event producing more than one break is presented.

3. The bulb antedates the evolutionary split ofD. melanogaster andD. simulans, since it is present in both species. The homology of the two arms of the duplication and therefore of the duplicated genes themselves, could be preserved by the possibility of crossing-over which exists in this type of rearrangement.

4. Some of the observed structural features are referred to certain internal forces in the chromosomes, such as the attraction between homologous chromomeres and the tension within the chromonemas.

5. Sexual dimorphism in regard to theX-chromosome in general and to the bulb in particular has been described. This is interpreted as an expression of a difference in the force of synaptic attraction in the cells of male and female.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Bridges, C. B. (1935). “Salivary chromosome maps.”J. Hered. 26, 60–4.

    Google Scholar 

  • Friesen, H. (1932). “Vergleichende Untersuchung der Häufigkeit somatischer Chromosomenbrüche beiDrosophila—Weibchen und Männchen.”Biol. J. 1, 47–51.

    Google Scholar 

  • Heitz, E. (1934). “Überα- undβ-Heterochromatin sowie Konstanz und Bau der Chromomeren beiDrosophila.”Biol. Z. 54, 588–609.

    Google Scholar 

  • Kossikoff, R. V. andMuller, H. J. (1935). “Invalidation of the genetic evidence for branched chromonemas in the case of Pale translocation.”J. Hered. (in press).

  • Muller, H. J. (1918). “Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors.”Genetics,3, 422–99.

    PubMed  CAS  Google Scholar 

  • —— (1935a). “The origination of chromatin deficiencies as minute deletions subject to insertion elsewhere.”Genetica,17, 237–52.

    Article  Google Scholar 

  • Muller, H. J. (1935b). “A viable two-gene deficiency phenotypically resembling the corresponding hypomorphic mutations.”J. Hered.

  • Panshin, L. (1935). “New evidence for the position effect hypothesis.”C.R. Acad. Sci. U.S.S.R. (in press).

  • Patterson, J. T. (1933). “The mechanism of mosaic formation inDrosophila.”Genetics,18, 32–52.

    PubMed  CAS  Google Scholar 

  • Prokofyeva, A. A. (1935). “The structure of the chromocentre.”C.R. Acad. Sci. U.S.S.R.

Download references

Author information

Authors and Affiliations

  1. Institute of Genetics, Academy of Sciences of the U.S.S.R., Moscow

    C. A. Offermann

Authors
  1. C. A. Offermann
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Offermann, C.A. Branched chromosomes as symmetrical duplications. Journ. of Genetics 32, 103–116 (1936). https://doi.org/10.1007/BF02982505

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02982505

Keywords

Search

Navigation