Citation
Konopka, Ronald Jerome (1972) Circadian Clock Mutants of Drosophila melanogaster. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/R04B-3425. https://resolver.caltech.edu/CaltechTHESIS:04012016-120503899
Abstract
Three mutants of Drosophila melanogaster have been isolated in which the free-running period of the circadian eclosion rhythm and the adult locomotor activity rhythm is affected. One mutant is arrhythmic, another has a short period of 19 hours, and the third has a long period of 28 hours. The mutants retain their phenotypes over the temperature range 18° to 25° C. All three mutants map near the tip of the X chromosome (distal to the centromere). By deficiency mapping, the short-period mutation has been localized to the 3B1-2 region. Complementation tests show that all three mutations affect the same functional gene.
Analysis of activity rhythms of individual mosaic flies indicates that the site of action of the short-period mutation is probably located in the head of the fly. A few activity patterns of split-head and mixed-head mosaics appear to possess both mutant and heterozygous components, suggesting that the fly head may contain two complete clocks capable of maintaining their periodicities independently.
The short-period mutation affects both the duration of the light-insensitive part of the oscillation and the degree to which the clock can be reset during the light-sensitive part of the oscillation.
Both the short-period and long-period mutant eclosion rhythms can be entrained to a period of 24 hours by a 12:12 light-dark cycle having a light intensity at least two orders of magnitude greater than that required to entrain the normal rhythm. The arrhythmic mutant does not entrain under these conditions. In the presence of a temperature cycle, however, the arrhythmic mutant does entrain, but its rhythm damps out when the temperature cycle is removed.
Evidence is presented that Pittendrigh's two-oscillator model for the clock in D. pseudoobscura applies to D. melanogaster as well. The three clock mutations primarily affect the light- sensitive driving oscillator. The arrhythmic mutation appears to have eliminated the driving oscillator while leaving the temperature-sensitive driven oscillator relatively intact.
Item Type: | Thesis (Dissertation (Ph.D.)) | ||||||
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Subject Keywords: | (Biochemistry and Chemistry) | ||||||
Degree Grantor: | California Institute of Technology | ||||||
Division: | Biology | ||||||
Major Option: | Biochemistry | ||||||
Minor Option: | Chemistry | ||||||
Thesis Availability: | Public (worldwide access) | ||||||
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Thesis Committee: |
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Defense Date: | 29 February 1972 | ||||||
Funders: |
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Record Number: | CaltechTHESIS:04012016-120503899 | ||||||
Persistent URL: | https://resolver.caltech.edu/CaltechTHESIS:04012016-120503899 | ||||||
DOI: | 10.7907/R04B-3425 | ||||||
Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||
ID Code: | 9639 | ||||||
Collection: | CaltechTHESIS | ||||||
Deposited By: | INVALID USER | ||||||
Deposited On: | 01 Apr 2016 20:14 | ||||||
Last Modified: | 01 Jul 2024 21:10 |
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