The Behavior of an Unstable Ring Chromosome in Drosophila melanogaster

Author: Hinton, Claude Willey

Year: 1954

Degree: Dissertation (Ph.D.)

Advisor: Sturtevant, Alfred Henry

Committee Member: Unknown, Unknown

Option: Biology

DOI: 10.7907/KKEX-R511

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

The behavior of "Catcheside's ring," an unstable closed-X chromosome [...] of Drosophila melanogaster, has been analyzed with the purpose of identifying the factors controlling the variable-level of [...] instability and of determining the mechanism of [...] elimination. The Y chromosome and the structure of the homologous rod-X chromosome were shown to have no influence on the frequency of [...] elimination. Since no segregating autosomal or sex-linked modifiers could be detected, the primary control of [...] instability must be limited to the [...] chromosome itself. The behavior of unstable small duplications derive from the [...] chromosome suggests that the locus of [...] instability must be in or near the [...] centromere region.

The frequency of [...] elimination is directly related to developmental temperature and to age of maternal [...] parents. Certain preliminary results incurred the speculation that a cytoplasmic factor is operative in [...] elimination.

Either anaphase lagging or the production of anaphase bridges by the [...] chromosome will account for its loss. The occurrence of [...] derivatives, deficient for either extensive or small euchromatic segments, suggests that anaphase bridges composed of continuous dicentric rings may be formed; however, such bridges do not necessarily constitute the exclusive means of elimination.

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