Publication Date


Document Type


First Advisor

Mittler, Sidney

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Drosophila melanogaster; Animal mutation; Heat--Physiological effect


A mutant strain of Drosophila melanogaster, designated as st mu-2 mus(3)301[^D1], carrying a third chromosome mutation for EMS sensitivity was utilized to determine its susceptibility to genetic damage by exposure to the combined and singular effects of heat and radiation. One day old males homozygous for this genotype were exposed to 38°C for 1 h, 1,200 R, or 38°C for 1 h followed by 1,200 R. The experimental parameters used were the dominant lethal (egg-hatching test) and loss and nondisjunction of the X and Y chromosomes by XO male-XXY female F^ analysis . Results were found to be dependent upon the type of treatment and the stage in spermatogenesis at treatment time. Heat was determined to have an enhancing effect on the mutagenic activity in the induction of dominant lethals, but not in chromosome loss or nondisjunction events. Radiation had a mutagenic effect on both experimental parameters. The conlbination of heat and radiation produced a higher frequency of dominant lethals but not loss of X and Y chromosomes or nondisjunction events. This seems to indicate that heat affects single gene changes but does not affect nondisjunction or whole chromosome loss. There appears to be synergism between heat and radiation in the production of dominant lethals.


Includes bibliographical references.


v, 41 pages




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