Ontogenes and Chromosome Nondisjunction in the <i>D. melanogaster</i> Meiosis

A mutation in an ontogene acts as a conditional dominant lethal: it is lethal certain genotype but not another. In total, 30 mutations of this type residing the Drosophila melanogaster X chromosome have been assayed for their ability to cause meiotic nondisjunction. The level nondisjunction females heterozygous appears be very high. share matroclinous daughters reaches 24.7% overall offspring and patroclinous males, 24.9%. Neither inversion opposite nor additional Y has any effect on balance XX X0 egg cells disturbed: exceptional are prevalent with normal sons, inverted chromosome. addition, 12% homozygous marker one maternal chromosomes (“equational” nondisjunction). “fading” parental also observed. Under experimental conditions, mutant ontogenes reside densely compacted chromosomes. We infer that DNA regions controlled compaction. It postulated genetic activity determined by compaction biophysical (electromagnetic) nature. cell, induce physical fields providing operation proteins. structure these distorted mutants ontogenes, thereby decreasing efficiency proteins and, consequence, causing defects.