Title: Contributions to the genetics of Drosophila melanogaster
Identifier: contributionsto00carn (find matches)
Year: 1919 (1910s)
Authors: Carnegie Institution of Washington; Morgan, Thomas Hunt, 1866-1945; Bridges, Calvin B. (Calvin Blackman), 1889-1938; Sturtevant, A. H. (Alfred Henry), 1891-1970
Subjects: Drosophila melanogaster; Heredity; Karyokinesis
Publisher: Washington, Carnegie Institution of Washington
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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THE ORIGIN OF GYNANDROMORPHS. 29 of 152 black 9 and 147 black cT, with no yellow-black offspring. Evidently, then, the testes came from a cell which had not mutated. While the "brown" color of the mosaic was like that produced by yellow acting with black, it is possible that the mutant gene was not the yellow already known, but a new yellow. (3) Among the grandchildren of the kst somatic sport a fly was found with a wing of an unusual type (text-fig. 9). This wing was about half the usual length and had almost exactly the form of min- iature, but there was none of the dark color normally present in miniature wings. This wing seems to have been a new mutant type, the mutation having occurred in the early embryonic cells of the fly. There have been quite a number of such occurrences, some, as in the present case, giv- ing striking differ- ences. (4) A fly ap- peared in vestigial stock (August 13, 1912) with one normal wing (text- fig. 10). It was described as a case of somatic atav- ism. An alterna- tive view is also possible, viz, that a somatic muta- tion occurred else- where, i. e., in an- other chromosome or in another region of the second chromosome, of such a sort that it neutralized the effect of both genes for vestigial. In the cells containing this mutant gene the conditions for normal wings are again restored. (5) a nd (6) Two further cases of mutation in the male were found by Sturtevant (not published); both were males throughout; one had forked bristles on one side of the body, although there were no forked flies in the immediate ancestry. The other had a dark body-color on part of the thorax, there being no sex-hnked dark body-color in the ped igree. Neither fly was tested. (7) I n a stock pure for red eyes, miniature wings, and j^ellow body- color a fly appeared with all the characters of its race except that one eye w as white with a fleck of red at its posterior edge (text-fig. 11).
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