. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. THE ORIGIN OF GYNANDROMORPHS. 67 the mother, and could have been the non-cross-over cut vermilion forked X. Neither cut nor vermilion would show in the female parts, since they would be recessive to their wild-t^-pe allelomorphs in the rugose forked X; and like- wise rugose would not show, for it would be recessive to its wild-type allelo- morph in the cut vermilion forked X. Both of these X's could not have come from the father, for in that case both eyes would have been rugose. One of
. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. THE ORIGIN OF GYNANDROMORPHS. 67 the mother, and could have been the non-cross-over cut vermilion forked X. Neither cut nor vermilion would show in the female parts, since they would be recessive to their wild-t^-pe allelomorphs in the rugose forked X; and like- wise rugose would not show, for it would be recessive to its wild-type allelo- morph in the cut vermilion forked X. Both of these X's could not have come from the father, for in that case both eyes would have been rugose. One of the forked X's therefore came from the mother. The left wing was cut, and since cut was present only in the mother, this X also must have come from the mother. Since the cut side did not show forked, this cut X must have been a cross-over anywhere between cut and forked. Thus we see that the egg contained two X's which were different, one being the non-cross-over cut vermilion forked X and the other the cross-over cut X, which is the normal condition of XX eggs produced by primary equational non-disjunction. This XX egg was fertilized by the rugose forked X sperm of the father, giving an XXX zygote. At the first segmentation division, double elimination or somatic reduction occurred, thereby enabling the fly to survive, but only at the price of becoming a gynandromorph. The paternal (rugose forked) and one of the maternal X's (cut vermilion forked) entered one cell, from which developed the female right side, which showed only one mutant char- acter, namely, forked. The cross-over maternal X (cut vermilion? rugose? not-forked) entered the other cell and gave rise to the male left side, showing the mutant character cut only. It should be noticed that in all four of these cases it has been the paternal X and one of the maternal X's that have come together into the female part, and that the male part was in each case maternal. This suggests that the essential feature of the reduc
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectkaryoki, bookyear1919
