. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. THE ORIGIN OF GYNANDROMORPHS. 9 Another gynandromorph (obtained by Sturtevant), text-figure 3, came from a mother that had in one second chromosome the genes for C„i and for curved, and in the other the genes for black and for vestigial. She may have had a third chromosome gene for crossing- over. The father was homozygous for black, purple, curved, plexus, speck, all in the second chromosome. Brothers and sisters were as expected; the black curved crossing over was 28 per cent. The fly
. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. THE ORIGIN OF GYNANDROMORPHS. 9 Another gynandromorph (obtained by Sturtevant), text-figure 3, came from a mother that had in one second chromosome the genes for C„i and for curved, and in the other the genes for black and for vestigial. She may have had a third chromosome gene for crossing- over. The father was homozygous for black, purple, curved, plexus, speck, all in the second chromosome. Brothers and sisters were as expected; the black curved crossing over was 28 per cent. The fly was black and showed no trace of purple, vestigial, curved, plexus, or speck. It was male on the left side, female on the right, except for head bristles. The genitalia were male. The fly was sterile. Unless the egg were a double cross-over for black vestigial curved, which is unlikely, it contained a black vestigial bearing chromosome. The sperm contained the five sec- ond-chromosome genes. Since the male parts showed none of these sec- ond-chromosome char- acters, except black, although all the rest ex- cept purple might have been visible, it is highly probable that the male parts contained both sec- ond-chromosomes. The result shows at least that the theory of chromo- some elimination is a more probable explana- tion than partial ferti- lization or multiple ferti- lization, and the result would be conclusive if the possibility of double crossing-over were rejected. Another case (found by Sturtevant, 4079 C, Oct. 31, 1917) occurred in a cross betweem a male with a normal X chromosome and pure for the second-chromosomal genes for black, purple, and curved, and a forked female that was heterozygous for the second-chromosomal genes for black, purple, and curved. The gynandromorph (plate 1, fig. 3) had a short wing on the left side, but the left foreleg was not male. The abdomen had the male banding and genitalia and contained two testes. No forked bristles were found in any p
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