Chromosomal Mosaicism in the Human and Chromosomal Change in vitro
Cellular activities can be regulated by mechanisms which stimulate or inhibit the enzymes already existing in the cell, or stimulate or inhibit their synthesis. Largely on the basis of findings in microbiology, the control of enzymatic patterns of activities in the life cycle of the cell is considered to involve, at least in part, regulation of enzyme synthesis at a genetic level . As the scheme in Fig. i shows, each DNA molecule is responsible for the synthesis of a corresponding RNA molecule (the “messenger”) which carries the information of the gene for the correct orientation of amino acids in the synthesis of specific protein. Whether a particular DNA sequence is active or not is determined by its trigger—the “operator” gene. Normally, the operator is repressed by a “repressor” substance produced by a “regulator” gene. Specific materials (perhaps including hormones ) which can inhibit the action of the repressor substance will allow the operator trigger to function and start transcription of the DNA strand. The regulation, or playing of the keyboard of genes, during the cell life cycle is so envisaged.
KeywordsAbnormal Karyotype Extra Chromosome Gonadal Dysgenesis Female Cell Chromosomal Mosaicism
Unable to display preview. Download preview PDF.
- 4.Karlson, P.: Biochemistry and mode of action of ecdysone, Proc. 2nd Int. Cong. Endocrinól. 1964, p. 416.Google Scholar
- 9.Lejeune, J., Gauthier, M., and Turpin, R.: Les chromosomes humaines en culture de tissus, C. R. Acad. Sci. (Paris) 248: 602, 1959.Google Scholar
- 14.Smith, D. W., Therman, E. M., Patau, K.A., and Inborn, S.L.: Mosaicism in a mother of two mongoloids, Am. J. Dis. Child, 104: 534, 1962.Google Scholar
- 19.Uchida, I.A., Patau, K., and Smith, D.W.: Dermal patterns of 18 and D, trisomics, Am. J. Human Genet. 14: 345, 1962.Google Scholar
- 24.Moore, K. L.: The genetics of sex determination and sex differentiation in man (historical review and discussion of new ideas), Manitoba Medical Review 42: 497, 1962.Google Scholar
- 28.Stone, D„ Akad, A.S., Noyes, C., and Lamson, E.: A multiple mosaic male mental retardate with presumptive 13–15 trisomy mosaicism and D/G translocation (possibly Di/G) (in press).Google Scholar
- 29.Yerganian, G.: Cytogenetic possibilities with Chinese hamster, Cricetulus barabensis griseus (abstract), Genetics 37: 638, 1952.Google Scholar