Abstract
The level of activity of the enzyme glucose-6-phosphate dehydrogenase was determinel in flies having seven different chromosomic constitutions. All those having an integral number of chromosomes [XAA, XXAA, XAAA, XXAAA, and XXXAAA (X=X chromosome, A=set of autosomes)] were found to have similar units of enzyme activity/mg live weight, while diploid females with a duplication and triploid females with a deficiency showed dosage effect. The amount of enzyme activity per cell, on the other hand, is also independent of the number of X's present but appears roughly proportional to the number of sets of autosomes.—It is proposed that dosage-compensated sex-linked genes are controlled by a positively acting regulatory factor(s) of autosomal origin. With this hypothesis it is possible to explain dosage compensation as a consequence of general regulatory mechanisms without invoking a special device which applies only to the X chromosomes.
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Selected References
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- Lucchesi J. C., Rawls J. M., Jr Regulation of gene function: a comparison of enzyme activity levels in relation to gene dosage in diploids and triploids of Drosophila melanogaster. Biochem Genet. 1973 May;9(1):41–51. doi: 10.1007/BF00485589. [DOI] [PubMed] [Google Scholar]
- Seecof R. L., Kaplan W. D., Futch D. G. Dosage compensation for enzyme activities in Drosophila melanogaster. Proc Natl Acad Sci U S A. 1969 Feb;62(2):528–535. doi: 10.1073/pnas.62.2.528. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Steele M. W., Young W. J., Childs B. Genetic regulation of glucose 6-phosphate dehydrogenase activity in Drosophila melanogaster. Biochem Genet. 1969 Aug;3(4):359–370. doi: 10.1007/BF00485720. [DOI] [PubMed] [Google Scholar]