Abstract
Spontaneous and EMS-induced mutations were accumulated for several generations on the second chromosome of Drosophila melanogaster by keeping this chromosome heterozygous under conditions of minimal natural selection. This article reports studies of heterozygous effects of these mutants.—Both lethal and mildly deleterious mutants have a deleterious heterozygous effect. There was no discernible difference between heterozygotes in which all the mutants were on one chromosome and those where the mutants were distributed over both homologs; thus the coupling-repulsion effect of Mukai and Yamazaki (1964, 1968) is not confirmed. The spontaneous polygenic mutants have a dominance of 0.4 to 0.5, and the same value is found at very low EMS doses. However, the value at higher EMS doses is only about half as high. Since the low doses have a large fraction of spontaneous mutants, the dominance of EMS mutants is less, in the range 0.1 to 0.3, but still larger than for lethals.
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Selected References
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- Greenberg R, Crow J F. A Comparison of the Effect of Lethal and Detrimental Chromosomes from Drosophila Populations. Genetics. 1960 Aug;45(8):1153–1168. doi: 10.1093/genetics/45.8.1153. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MUKAI T., CHIGUSA S., YOSHIKAWA I. THE GENETIC STRUCTURE OF NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. II. OVERDOMINANCE OF SPONTANEOUS MUTANT POLYGENES CONTROLLING VIABILITY IN HOMOZYGOUS GENETIC BACKGROUND. Genetics. 1964 Oct;50:711–715. doi: 10.1093/genetics/50.4.711. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MULLER H. J. Our load of mutations. Am J Hum Genet. 1950 Jun;2(2):111–176. [PMC free article] [PubMed] [Google Scholar]
- Maruyama T., Crow J. F. Heterozygous effects of x-ray induced mutations on viability of Drosophila melanogaster. Mutat Res. 1975 Feb;27(2):241–248. doi: 10.1016/0027-5107(75)90083-4. [DOI] [PubMed] [Google Scholar]
- Mukai T., Chigusa S. I., Mettler L. E., Crow J. F. Mutation rate and dominance of genes affecting viability in Drosophila melanogaster. Genetics. 1972 Oct;72(2):335–355. doi: 10.1093/genetics/72.2.335. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mukai T. Viability mutations induced by ethyl methanesulfonate in Drosophila melanogaster. Genetics. 1970 Jun;65(2):335–348. doi: 10.1093/genetics/65.2.335. [DOI] [PMC free article] [PubMed] [Google Scholar]